State v. Plude

PATIENCE DRAKE ROGGENSACK, J.

¶ 1. We are asked to review a decision of the court of appeals1 that affirmed the circuit court's2 order denying Douglas Plude's motion for postconviction relief from his conviction of first-degree homicide, contrary to Wis. Stat. § 940.01 (2005-06). Plude's conviction was based on the death of his wife, Genell Plude. He sought to have the jury's verdict set aside and to have the charges dismissed or to have a new trial based on two allegations of error.

*32¶ 2. First, Plude discovered after the completion of his trial that one of the State's expert witnesses, Dr. Saami Shaibani, who testified that the positions in which Plude said he found his wife's body were physically impossible3 for an unconscious person to maintain, lied under oath about his credentials. Plude claims this is newly-discovered evidence that requires a new trial. Second, he contends that the State's failure to timely provide potentially exculpatory evidence, in the form of the content of computer hard drives and a copy of his wife's death certificate, deprived him of his constitutional right to present a defense.

¶ 3. We conclude that the discovery that Shaibani testified falsely about his credentials is newly-discovered evidence that gives rise to a reasonable probability that, had the jury heard Shaibani's misrepresentation about his credentials, it would have had a reasonable doubt as to Plude's guilt. Accordingly, we vacate Plude's conviction and remand to the circuit court for a new trial.4

I. BACKGROUND

¶ 4. The State's theory is that Plude murdered Genell by poisoning her with Fioricet-codeine and then drowning her in toilet bowl water in their home. Plude contends that Genell committed suicide by taking an overdose of drugs, which served as a catalyst for a fatal occurrence of pulmonary edema.5 In other words, Plude *33theorizes that Genell drowned in fluids created by her own body.

¶ 5. In February, 1999, eight months before Genell's death, Genell and Plude began experiencing marital problems. The couple separated for a short time that spring, and Genell went to live with her parents in Minneapolis. The couple soon reconciled, however, and Genell again resided with Plude and his mother in their shared home in Land O' Lakes, Wisconsin.

¶ 6. Marital strain continued. On the day before her death, Genell told her mother that she had quit her job and that she wanted to leave Plude. Genell arranged for her parents to pick her up from her home early the next morning so that she could return to Minneapolis to live with them.

¶ 7. On the evening before her death, according to Plude, he and Genell went to bed together. A short time later, Genell got up to get medication for a headache. Plude went to sleep and in the hour between 5-6 a.m., Plude noticed that Genell was not in bed. He testified at the medical inquest that after calling for Genell he found her in the bathroom slumped over the toilet. He noticed that her hands were blue and her face was in the toilet bowl, which contained vomit.

¶ 8. The positions in which Plude claimed he found Genell were the subject of much testimony at trial. He told Officer Jennifer Kroschell the morning of Genell's death that he found Genell crouched on her knees facing the toilet, with her head pitched forward so that her face was in the toilet bowl, and with her arms draped loosely at either side. Officer Kroschell testified that Plude was "hysterical" when offering his account. Plude described a somewhat different position of Genell's body at the medical inquest. There, Plude described Genell as slumped over the bowl, her head *34cocked to the left, with her face and hair in the water. Her left arm was draped around the bowl, with her right arm hanging loosely at her foot. She was situated on her knees.

¶ 9. According to Plude, he noticed vomit in the toilet; pulled Genell away from the toilet; screamed for his mother; and performed CPR on Genell. In his panic at her condition, he cracked her sternum while performing CPR. Plude's mother awoke and became panicked upon observing the scene. Her panic precluded her from calling 911, so Plude stopped performing CPR to do so.

¶ 10. Paramedics arrived, and Plude assisted them in attending to Genell.6 One of the paramedics, Sid Baake, testified that when he arrived at the Plude home, Plude was still performing CPR on Genell. Baake testified that Plude was crying, "I think that she is gone. Help me. Help me."

¶ 11. Genell was conveyed to a hospital, where she was pronounced dead. An attending nurse in the emergency room overheard Plude say to Genell's corpse, "I told you not to leave me."

¶ 12. Investigation of her death uncovered that Genell had ingested 40 Fioricet with codeine capsules. Genell had obtained a prescription for the drug some time in 1997.

¶ 13. Dr. Kenneth Sullivan, the emergency room doctor who attended to Genell, testified at trial. He concluded that Genell drowned because Genell had fluid in her lungs. Although the fluid was consistent with pulmonary edema, he could not determine to a reasonable degree of scientific certainty whether the fluid came from pulmonary edema or from a source *35outside her body. Dr. Sullivan also noted a bruise on the side of Genell's neck. He testified that the appearance of the bruise would have required "some force" beyond just the weight of her head.

¶ 14. Beyond the presence of fluid in her lungs, which may have come from the toilet bowl or may have come from her own bodily function, the presence of lethally high levels of drugs were in Genell's body when she died. Casey Collins, a toxicologist at the Wisconsin State Crime Lab, testified that he took blood samples, urine samples, a liver sample, a kidney sample, and a stomach content sample from Genell's body. He also took samples of the toilet bowl water. Genell's body and the toilet bowl water showed the presence of the same four drugs: Acetaminophen (Tylenol), codeine (an opiate), butalbital (a barbiturate), and caffeine.

¶ 15. Collins testified to the lethal levels of each drug, and the amount Genell had in her body. Codeine is lethal at a level of 1.6 mg/liter, and Genell had 20 mg/liter in her body. Butalbital is lethal at a range of 13-26 mg/liter, and Genell had 18 mg/liter in her body. Acetaminophen is lethal at a level of 160 mg/liter, and Genell had 213 mg/liter in her body. Moreover, there were only a few milligrams of these drugs left in her stomach, indicating that the drugs were almost completely absorbed before she vomited.

¶ 16. Given the drug doses in Genell's body, Dr. Mitra Kalelkar, the Assistant Chief Medical Examiner at the Cook County, Illinois Medical Examiner's Office, testified that Genell drowned as a result of "combined drug intoxication" that caused pulmonary edema. Dr. Kalelkar testified that the weight of Genell's lungs was consistent with pulmonary edema. He testified that the Fioricet-codeine in Genell's body slowed her heart rate, which in turn caused her circulation to slow, which in *36turn caused fluid to accumulate in her lungs. Ultimately, Dr. Kalelkar concluded that Genell drowned due to reduced blood circulation caused by the presence of drugs in her body.

¶ 17. Dr. Kalelkar also testified to Genell's condition at her death. He said that there was no indication that Genell inhaled any toilet bowl water. He said that the bruise on her neck was not the result of an outside force pressing her neck against the rim of the toilet; rather, the bruise on her neck resulted simply from her lying on the rim of the toilet. In addition, he stated that there were no injuries to her neck and trachea in places one would expect to find them if her head had been forced into the toilet bowl.

¶ 18. Moreover, although Dr. Kalelkar concluded that Genell died from a drug overdose, he also opined that she did not die from a forced overdose. He testified that the amount of drugs found in Genell's body indicates that, if she did not take them voluntarily, they would have to have been forcibly administered to her; however, her body showed no evidence that she had engaged in a struggle.

¶ 19. Dr. Kalelkar provided one last item of note. While the nurse in the emergency room found Plude's statement that "I told you not to leave me" disturbing, Dr. Kalelkar testified that such a statement is not unusual. He testified that the statement was "a manifestation of the anger which is . . . part of the grieving process."

¶ 20. Dr. Robert Huntington, the pathologist who performed Genell's autopsy, added to the cacophony of disparate medical opinions regarding the cause of Genell's death. For instance, Dr. Huntington testified that the bruise on Genell's neck was the result of "blunt force" administered while Genell was still alive. He also *37opined that the fluid in Genell's lungs was inconsistent with pulmonary edema. He testified that when pulmonary edema occurs, the lungs fill with fluid in concentrated places. However, the fluid in Genell's lungs was spread over a wide area; therefore, it was his conclusion that the fluid likely came from a source outride of her body.7 Dr. Huntington also testified that Genell had enough drugs in her bloodstream to kill her. His ultimate conclusion was that Genell "died of drug intoxication probably abetted by drowning." He testified that Genell's death was either a suicide or a homicide, but he could not say to a reasonable degree of scientific certainty which had occurred.

¶ 21. Dr. Huntington testified that his lack of clarity over the manner of Genell's death stemmed from certain facts that he could not explain. For example, he said that he would want the neck bruise explained; he would want to know why her limp body stayed upright around the rim of the toilet instead of rolling back onto the floor; and he did not know what accounted for the hemorrhaging in her lungs.

¶ 22. Julius Ballanco, a consulting engineer, testified regarding the physical mechanics of a toilet. He testified that toilets are designed such that the mouth and the nose cannot be submerged accidentally and simultaneously into the toilet bowl water, but that it is possible for a person accidentally to submerge the forehead and nose into the toilet bowl water. In addition, Ballanco opined that the toilet in the Plude home had not been flushed because it contained vomit when Plude found Genell. Ballanco was able to surmise, *38however, that there had been approximately one pint of water displaced from the toilet. He concluded that the displacement of this amount of water would have had to come from some force greater than vomiting.

¶ 23. We now turn our attention to the testimony of Shaibani. Shaibani, who is not a medical doctor, set forth his credentials under oath and in his curriculum vitae admitted as an exhibit at trial. He represented himself as a clinical associate professor at Temple University and as a specialist in "injury mechanism analysis."8 He said that as part of his duties at Temple University he taught physicians and surgeons about injury. He described injury mechanism analysis as a field of scientific study that "combines physics, trauma, and engineering" "to determine whether or not an injury could have been caused by the circumstances involved." With regard to his duties as a clinical assistant professor at Temple University and his expertise in injury mechanism analysis, Shaibani testified as follows:

Q: Why don't you explain to the jury exactly what injury mechanism analysis is?
A: The injury mechanisms analysis is a scientific study to determine whether or not an injury could have been caused by the circumstances involved. It combines physics, trauma, and engineering.
Q: How do you get to be someone who specializes in injury mechanisms analysis?
*39A: I ask myself that every day, in fact.
But, basically, you have to have a background in each one of those three disciplines that I mentioned.
You need to have a good understanding of physics because that's one of the main sciences.
You need to have a background in trauma because that's what injury relates to.
Then it helps if you have a background in engineering, if nothing else, to prove that you are a practical animal.
Q: As a clinical professor, what do you consider your responsibilities to be?
A: I have two main areas of responsibilities. I teach and I do research. My teaching is to physicians and surgeons, fully qualified medical doctors, and I teach them about injury. It's one of those curious things that they don't learn about injury in medical school. So I explain how injuries are caused, how they can be prevented, how they can be treated under certain circumstances.

Shaibani also testified that he has a Master's Degree in Crystal Physics and Metallurgy, a Master's Degree in Science of Materials, and a Ph.D. in Material Physics, all from Oxford University.

¶ 24. Shaibani was received as an expert in the area of injury mechanism analysis by the circuit court. He testified regarding the interrelation between the mechanics of the human body and the laws of physics. He explained the effect of the interrelation on the positions in which Plude said he found Genell's body, and he explained whether she could have lost consciousness and drowned herself in the toilet bowl water.

*40¶ 25. Shaibani performed a number of experiments with various human models having Genell's reported height and weight9 to replicate the positions in which Plude explained he found Genell. The State's expert, Dr. Huntington, testified that it was more likely than not that the fluid in Genell's lungs came from toilet bowl water rather than from her own bodily processes, i.e., from pulmonary edema. Shaibani took Dr. Huntington's conclusion further. He testified that his experiments indicated to a reasonable degree of scientific certainty that Genell could not have inhaled toilet bowl water on her own; that it would have required 60 pounds of pressure to the back of her head to get her face in the toilet bowl water and keep it there.

¶ 26. After describing his experience and purported expertise, Shaibani testified that he used a model to simulate the position in which Plude first claimed he found Genell:

Q: What was the first step in the testing that you did to answer each of these questions?
A: I began at the beginning. One of the first things that I'm aware of is a statement that the defendant made to Deputy Krosschell [sic]. I'm reading from that report in which she relates the following. Douglas stated he observed Genell on her knees in front of the toilet with her arms down to the side and her face in the toilet bowl. That's the first statement that he has given to anyone, so I'm going to begin at the beginning and see what the sign says, as far as looking at that is concerned.
Q: Why don't you tell the jury whát you did in that regard. Could you indicate what exhibit you are looking at for the record and how you are going to do that for the jury?
*41A: Yes, sir. This is State's Exhibit 184. It has the caption, defendant's first story, and there is some space on this exhibit for me to show the results of the test that I conducted to look at this.
A: So if we look at this description given by the defendant, that Genell is on her knees, with her arms down to the side and her face in the toilet bowl, I got somebody of the same height, the same weight, and the same gender, with the same toilet bowl that you see here, and I asked her to try and put her head in the toilet, and, for purposes of identification, this is Photograph 2774.
Q: Now, in that position, was the head able to go into the water?
A: In some circumstances, the head — and when I say "the head," I mean the forehead and the top of the head — possibly could, but at no stage could the face be in the water. It's important to make that distinction because the defendant says her face was in the toilet bowl. It becomes ambiguous as to what part of the bowl you are referring to. Later on, we'll be looking at the face in the water.

¶ 27. Shaibani then conducted a similar experiment with the chosen model in the second position in which Plude explained he found Genell:

Q: Let's go to the second set. Again, refer to the exhibit, if you would. This is?
A: Oh, thank you, sir. Defendant's second story. We see a significant change now in how he reports the circumstances of how he found Genell.
*42Q: Go ahead.
A: I've got at least six different occasions where he states her face was into the water. Her face was in the water. Her face was in the water. Her face was in the water there. At least four instances that I have just told you where he says, again and again, her face, not her head, is in the water, not the bowl.
On other occasions, he talked about her head being in the bowl, but now we've got an important change that, on four instances, at least that I can find, her face was into the water.
So this is a new development. Her face is now in the water is what the defendant is saying.
In addition to that, he describes that she was cocked to one side, kind of on her hip with her left arm on the bowl, her right hand was hanging down.
So now we've got a lot more detail than we had in the first story. No longer the hands on either side of the knees that we saw in those first photographs. We've got a completely different scenario.
A: .. .This is interesting because, if your left hand is in the position that we think the defendant is describing, then, because your arm is of a certain length and your body is arranged a certain way, if you are five foot eight and a half inches and you weigh 140 pounds and you are female, things fit together a certain way anatomically, and, under the circumstance, for this particular interpretation, not all of them, but for this particular interpretation, that face is clearly not going to be in the water.
Then you've got your chest getting in the way, you've got your neck getting in the way, and there is *43no way, physiologically or anatomically under this one way of looking at it, for the face to be in the water.
A: What was interesting, when we positioned this particular volunteer, with the legs coming to the left towards us as we look, is that once you are in that position, and I say to the volunteer, let your muscles go limp and relax, a very surprising thing happened, and that is, she fell out. You can see that I gallantly came to the rescue and stopped her head falling on the floor because that's my hand there. So she is falling out. She is trying to kind of artificially prop herself up there using muscle tone, muscle tension. And the moment I said to her, relax, let go, whoops, she was out of there, she was gone.
Q: Now, for that set of circumstances and the experimenting that you did, is what resulted there, would that be the force of gravity that we talked about?
A: Yes, sir. These are experiments. After we've gone through these sequences, I'll then show the interpretation of these results analytically.
Q: But, for purposes of that one experiment, is the result going to be the same result every time that set of circumstances exists, to a reasonable degree of scientific certainty?
A: Yes, sir, or a very small variation on the theme. It's going to be substantially similar.

¶ 28. In summation of how the models depicted the first two positions in which Plude claimed he found Genell, Shaibani testified that the models could not maintain either position:

*44A: The issue here is that you can shuffle this around any way you want. The overall result is going to be, broadly similar, that gravity will take over the body in the first sequence. Gravity will take over the body in the second sequence and cause the body to slump out and down to the right.
Q: Is that your opinion, to a reasonable degree of scientific certainty?
A: Yes, sir, it is.

¶ 29. From here, Shaibani went on to talk about "force." His experiments revealed that his models could not keep their heads in the toilet bowl once they relaxed their muscles, because the force of gravity caused them to "fall out," down and to the right. So, in order for Genell's head to have been in the bowl, as Plude claimed he found her, Shaibani testified that her head had to have been kept there by a force, and that force would be approximately 60 pounds of pressure:

A: ... If you weigh 140 pounds, it turns out that nine pounds of your body weight is above your neck; sawdust or otherwise between your ears. Now, if there are nine pounds on your head, then there must be only 131 left over for the rest of your body. So we put a demarcation now of two different forces. We can break the body down as far as it pivoting about this fulcrum.
A: So we have to first balance the weight, which is divided up into nine pounds on the head and 130 pounds or 131 pounds on the rest of her body. You can see that, if we look at this as a fulcrum, then the left-hand side of her body, the main part of her body is going to go down and the head is going to go up.
*45Q: Is that principle an opinion to a reasonable degree of scientific certainty?
A: Yes, it is. But we haven't finished what we are doing here because I've got only two forces. What about the force on the knee, the hands, and the feet? We've got to include those. So the hands were one inch in front of the fulcrum; there was a force there of five pounds. The knees, we had a force of about 90 pounds going up. The feet, we had a force of about 25 pounds going up. Then, one final force is 20 pounds on that part of the upper body. So each one of these forces is going to try and make Genell go down and rotate her clockwise into the bowl or they are going to rotate her counterclockwise out of the bowl. If you add up all of these forces and take into account the distances which we saw were important in our seesaw demonstration [omitted from this excerpt], then overwhelmingly her body wants to come out. There is just too much weight outside the toilet, even though it has been supported at the knees and at the feet. There is still too much weight pulling her down, down, down, out, out, out, away, away, away from that water. So that says, well, what would you have to do to get her head into the water?
Q: Her face into the water?
A: Her face into the water. If you want her face into the water, and the laws of physics tell us that the body is rotating out, you have to counteract that. You have to apply an external force at some attack distance to make sure that the head stays down as opposed to going out. This is an external force.
All of these other forces deal with what Genell is doing with the floor supporting her. These are the only things she has control over and she is going to go out of that toilet, down and away. The only way her head can go down is if there is an external force applied.
*46Q: Were you able to calculate how much force would be required to get Genell's face into that bowl and suspend it there?
A: Yes. You can do that with the laws of physics. For over 300 years, what that external force is at, that attack distance, consistent with her body, and that result is on the order of 60 pounds, if you wanted to pick a typical value.
Q: Now, I want you to look at the defendant over there. Would somebody about that big in height be able to exert that kind of outside force?
A: Very easily, sir, yes.
Q: What kind of force would it take to keep the head there?
A: Once you've got it down and the body is moving, it's easier to keep something moving than it is to start it moving. So once you've got it down, you can maintain that force with relatively little effort.
Q: I have nothing further.
And — one question: Is that to a reasonable degree of scientific certainty; that opinion?
A: Yes, sir, it is.

¶ 30. The jury convicted Plude of first-degree homicide, and he was sentenced to life in prison. After the verdict, Plude discovered that Shaibani had lied on the witness stand, and he moved for postconviction relief.10 *47The circuit court concluded that even though the State had stipulated that Shaibani was not a clinical professor at Temple University, there was no evidence that his false statements "concerning his curriculum vitae made his opinions unreliable, therefore, no prejudice to the defendant has been shown." The circuit court did not evaluate whether a reasonable probability existed that a different result would be reached at a new trial if the jury knew that Shaibani misrepresented his credentials. The court of appeals affirmed the circuit court's denial of a new trial based on newly-discovered evidence because it concluded that "Plude intimated he was only challenging Shaibani's credibility, not his qualifications to testify as an expert." State v. Plude, No. 2005AP2311-CR, unpublished slip op., ¶ 28 (Wis. Ct. App. Mar. 6, 2007). Plude petitioned for review, which we granted.

II. DISCUSSION

A. Standard of Review

¶ 31. Plude requests a new trial through his contention that the discovery of Shaibani's misrepresentations constitutes newly-discovered evidence. The decision to grant or deny a motion for a new trial based on newly-discovered evidence is committed to the circuit court's discretion. State v. Boyce, 75 Wis. 2d 452, 457, 249 N.W.2d 758 (1977). A circuit court erroneously exercises its discretion when it applies an incorrect legal standard to newly-discovered evidence. State v. McCallum, 208 Wis. 2d 463, 474, 561 N.W.2d 707 (1997).

*48B. Newly-Discovered Evidence11

1. General principles

¶ 32. In order to set aside a judgment of conviction based on newly-discovered evidence, the newly-discovered evidence must be sufficient to establish that a defendant's conviction was a "manifest injustice." State v. Krieger, 163 Wis. 2d 241, 255, 471 N.W.2d 599 (Ct. App. 1991). When moving for a new trial based on the allegation of newly-discovered evidence, a defendant must prove: "(1) the evidence was discovered after conviction; (2) the defendant was not negligent in seeking the evidence; (3) the evidence is material to an issue in the case; and (4) the evidence is not merely cumulative." McCallum, 208 Wis. 2d at 473. If the defendant is able to prove all four of these criteria, then it must be determined whether a reasonable probability exists that had the jury heard the newly-discovered evidence, it would have had a reasonable doubt as to the defendant's guilt. Id.

¶ 33. "A reasonable probability of a different outcome exists if 'there is a reasonable probability that a *49jury, looking at both the [old evidence] and the [new evidence], would have a reasonable doubt as to the defendant's guilt.'" State v. Love, 2005 WI 116, ¶ 44, 284 Wis. 2d 111, 700 N.W.2d 62 (citation omitted). A court reviewing newly-discovered evidence should consider whether a jury would find that the newly-discovered evidence had a sufficient impact on other evidence presented at trial that a jury would have a reasonable doubt as to the defendant's guilt. McCallum, 208 Wis. 2d at 474. This latter determination is a question of law. See id. Manifest injustice has been shown and a new trial must be ordered when: (1) the four factors of newly-discovered evidence are established; and (2) a court determines that had a jury heard the newly-discovered evidence, it would have had a reasonable doubt as to the defendant's guilt. See Krieger, 163 Wis. 2d at 255.

2. The parties' positions

¶ 34. The State concedes that with the revelation that Shaibani lied under oath, Plude has satisfied the four criteria for proving newly-discovered evidence of the type that may cause the ordering of a new trial. However, the State argues those criteria are not sufficient to warrant a new trial here because Shaibani's false testimony does not give rise to a reasonable probability that a different verdict would have been reached at trial. The State admits that if Shaibani's false testimony about his fictitious professorship at Temple University had been revealed during Plude's trial, the revelation would have unquestionably diminished Shaibani's credibility in the eyes of the jury. However, the State nonetheless argues that Shaibani's credibility would not have been tarnished to the degree that the jury would have found his testi*50mony unreliable and found Plude not guilty, because the evidence marshaled against Plude at trial was overwhelming.

¶ 35. Plude counters the State's arguments by contending that there is a reasonable probability that Shaibani's testimony sealed the jury's verdict of guilty. Plude asserts that it was Shaibani's testimony that cast doubt on Plude's descriptions of the positions in which he found Genell's body. This was significant to Plude's defense that Genell committed suicide by a drug overdose. It was also significant to the State's theory that Genell drowned in water from the toilet bowl rather than in her own bodily fluid. Plude asserts that if he had been able to impeach Shaibani, three results would have followed: (1) Shaibani's overall credibility as an expert witness would have been attacked effectively;12 (2) the methods Shaibani used to support his testimony that Genell could not have been found in the positions Plude described would have been discredited; and (3) Shaibani's conclusion that Genell could not have drowned in toilet bowl water unless her head was forced into the toilet bowl would have been undermined. Accordingly, Plude maintains that Shaibani's false testimony no doubt affected the jury's verdict because Shaibani played the preeminent role in linking Plude to the inculpatory testimony of Dr. Huntington, who opined that Genell drowned in toilet bowl water, rather than from pulmonary edema.

*513. Reasonable probability

¶ 36. We conclude that in a trial rife with conflicting and inconclusive medical expert testimony about a case the circuit court observed was based on "circumstantial evidence," there exists a reasonable probability that, had the jury discovered that Shaibani lied about his credentials, it would have had a reasonable doubt as to Plude's guilt. Our conclusion is based on Shaibani's testimony as a quasi-medical expert notwithstanding his lack of a medical education and on the link that Shaibani's testimony provided to other critical testimony that related to the manner of Genell's death.

¶ 37. Shaibani testified that based on his knowledge about the mechanics of the human body, Genell's body could not have been found in the positions that Plude described and that her nose and mouth could not have submerged in toilet bowl water without someone forcing her face under the water. Because Shaibani had no medical education where the human body would have been studied, he lent support to his opinions about the human body by the description of his work as a clinical professor at Temple University. He said that at Temple University he taught "physicians and surgeons, fully qualified medical doctors, and I teach them about injury [to the body]," even though he had no medical degree. He specifically opined that Genell could not have inhaled toilet bowl water on her own; that it would have required 60 pounds of pressure, pressure that he said Plude "very easily" could have exerted, to the back of her head to get her face in the toilet bowl water and keep it there.

¶ 38. Plude cites Giglio v. United States, 405 U.S. 150 (1972), as support for his position. However, Giglio *52was driven by a violation of due process, rather than, as here, by newly-discovered evidence that does not implicate a violation of due process.13 However, just as in Giglio, Shaibani's diminished credibility as an expert due to his misrepresentation may have affected the reliability of his testimony as well because only an expert witness could testify as to the opinions he gave.

¶ 39. In Giglio, the Supreme Court reversed Giglio's conviction for passing forged money orders because the State did not disclose that its key witness, a co-conspirator with Giglio, was promised immunity in exchange for his testimony. Id. at 150-53. The co-conspirator had testified at trial that he did not have an immunity agreement with the government, and the prosecuting attorney confirmed this in closing argument. Id. at 151. Even though the prosecuting attorney was unaware that an immunity agreement had been made, the court attributed the knowledge of the agreement to the prosecuting attorney. Id. at 154.

¶ 40. As part of its analysis of whether Giglio should be granted a new trial, the Supreme Court observed that a new trial is required if there exists a reasonable likelihood that the false testimony of a witness affected the judgment of the jury:

When the "reliability of a given witness may well be determinative of guilt or innocence," nondisclosure of evidence affecting credibility falls within this general rule. ... A new trial is required if "the false testimony could ... in any reasonable likelihood have affected the judgment of the jury."

Id. at 154 (citations omitted).

*53¶ 41. In much the same way, Shaibani's misrepresentation may have been determinative of Plude's guilt or innocence. For example, Dr. Kenneth Sullivan, the emergency room doctor, concluded that Genell drowned, and that her drowning could have been due to pulmonary edema or to inhalation of toilet bowl water. He did not testify to either possibility to a reasonable degree of scientific certainty. However, Dr. Sullivan concluded that the bruise on Genell's neck would have required "some force" other than the weight of her head.

¶ 42. On the other hand, Dr. Kalelkar, of the Cook County Medical Examiner's Office, concluded that Genell died of "combined drug intoxication" that led to her drowning in her own bodily fluid, i.e., due to pulmonary edema. He explained that the weight of Genell's lungs was consistent with pulmonary edema; that the drugs caused her heart rate to slow, which caused her lungs to fill with her own bodily fluid. In contrast to Dr. Sullivan, Dr. Kalelkar concluded that there was no indication that Genell inhaled any toilet bowl water. Further, he testified that the bruising on her neck resulted from the weight of her head resting over the rim of the toilet bowl. He also said that there was no injury to her neck and trachea of the type that one would expect to find if her head had been forced into the toilet bowl.

¶ 43. Meanwhile, Dr. Huntington, the pathologist who performed Genell's autopsy, concluded that the fluid in her lungs was inconsistent with pulmonary edema, but he did not opine to a reasonable degree of scientific certainty that she drowned from inhaling toilet bowl water. He also concluded that she had enough drugs in her body to kill her, as had Dr. Kalelkar. Dr. Huntington's ultimate conclusion was that *54she died of "drug intoxication probably abetted by drowning." Dr. Huntington opined Genell's death was either a suicide or a homicide, but he could not say which had occurred. Moreover, he concluded that the bruise on her neck came from "blunt force."

¶ 44. Although Ballanco's testimony may be perceived as inculpatory because he testified that toilet bowls are designed so that one cannot accidentally submerge both the nose and mouth under the water, Ballanco also testified that it was possible accidentally to submerge the forehead and nose in the water. His two conclusions would have been insufficient for the jury to convict Plude because they did not rebut Plude's theory that Genell drowned as a result of pulmonary edema, rather than as a result of forced drowning.

¶ 45. The expert medical testimony also does not rule out the possibility that Genell drowned as a result of pulmonary edema. Accordingly, Ballanco's testimony, in contrast to Shaibani's testimony, does not directly implicate Plude in Genell's drowning. For example, Ballanco said nothing about the force necessary to submerge Genell's nose and mouth under the water in the toilet bowl, but Shaibani did. Ballanco also said nothing about the credibility of Plude's descriptions of the position of Genell's body when he found her, but Shaibani did. Ballanco's testimony leaves open the question of whether Genell drowned due to pulmonary edema caused by the effect of drugs on her bodily functions. Shaibani's opinion testimony sets out facts that cause Plude's credibility to be questioned. In so doing, it raised the probability that forced drowning occurred, and by inference, it lowered the probability that drowning due to pulmonary edema occurred.

¶ 46. In sum, with the exception of Dr. Kalelkar's opinion, which was exculpatory of Plude, the medical *55expert opinions with regard to Genell's manner of death were inconclusive. Dr. Kalelkar concluded to a reasonable scientific certainty that Genell drowned from pulmonary edema; Dr. Sullivan concluded that it was likely, but not a reasonable scientific certainty, that Genell drowned from pulmonary edema; Dr. Huntington concluded that it was likely, but not a reasonable scientific certainty, that Genell drowned from inhaling toilet bowl water. Shaibani affirmed Dr. Huntington's opinion and linked Plude to Genell's inhalation of toilet bowl water. Therefore, Shaibani's testimony was a critical link in the State's case.

¶ 47. Wisconsin law has long held that impeaching evidence may be enough to warrant a new trial. Birdsall v. Fraenzel, 154 Wis. 48, 142 N.W.2d 274 (1913). In commenting on the discovery that a trial witness could read and write English after he testified to the contrary, we stated: "It may well be that newly discovered evidence impeaching in character might be produced so strong as to constitute ground for a new trial; as for example where it is shown that the verdict is based on perjured evidence." Id. at 52 (emphasis added).

¶ 48. Our conclusion that Shaibani's false testimony about his credentials is a significant link to establishing unassisted drowning in water from the toilet bowl as a cause of Genell's death is distinguishable from the court of appeals' conclusion in State v. Sprosty, 2001 WI App 231, 248 Wis. 2d 480, 636 N.W.2d 213. In Sprosty, the court of appeals concluded that there was no reasonable probability that false testimony by a witness, who misrepresented his credentials, would lead to a different outcome because the witness maintained his expertise in spite of the false testimony and another expert corroborated his substantive testimony. Sprosty, 248 Wis. 2d 480, ¶ 34. Here, Shaibani's *56credentials were not maintained subsequent to his misrepresentation and no expert corroborated his substantive testimony.

¶ 49. The inconclusive inculpatory medical expert testimony at Plude's trial leads us to conclude that Shaibani's quasi-medical expert testimony creates a reasonable probability that the jury hearing of Shaibani's false testimony about his credentials would have had a reasonable doubt as to Plude's guilt. The circuit court did not apply the legal standard of whether there is a reasonable probability that the jury hearing of Shaibani's false testimony would have had a reasonable doubt as to Plude's guilt. Failing to apply the proper legal standard is an erroneous exercise of discretion. McCallum, 208 Wis. 2d at 473. Accordingly the circuit court erroneously exercised its discretion when it did not order a new trial for Plude.14

III. CONCLUSION

¶ 50. We conclude that the discovery that Shaibani testified falsely about his credentials is newly-discovered evidence that gives rise to a reasonable probability that had the jury heard of Shaibani's misrepresentation about his credentials, it would have had a reasonable doubt as to Plude's guilt. Accordingly, we vacate Plude's conviction and remand to the circuit court for a new trial.

*57By the Court. — The decision of the court of appeals is reversed, and the cause is remanded to the circuit court.

State v. Plude, No. 2005AP2311-CR, unpublished slip op. (Wis. Ct. App. Mar. 6, 2007).

The Honorable James B. Mohr of Vilas County presided.

Plude's accounts of Genell's position when he found her varied.

Because we grant a new trial, we do not consider Plude's arguments with respect to the computer hard drives and the death certificate.

Pulmonary edema is the filling of the lungs with fluid created by one's own body.

At one point, Plude had been employed as a paramedic.

Apparently, no testing was done on the fluid in Genell's lungs to see if it was consistent with the water from the toilet bowl or with bodily fluid.

Plude claims that Shaibani invented this field of specialty and that "[n]o other person on the face of the earth considers himself or herself an expert in the field of injury mechanism analysis." Pet. Br. at 6.

Genell was reported to stand approximately 5 feet, 8 inches and weigh approximately 140 pounds.

Plude states that he discovered that Shaibani misrepresented himself when Shaibani attempted to testify untruthfully before a North Carolina court.

Based on Shaibani's misrepresentations, Plude seeks to have his conviction vacated and a new trial ordered on three separate bases: (1) Shaibani's false testimony violated his right to due process of law; (2) Shaibani's testimony is incredible as a matter of law; and (3) Shaibani's false testimony, which the State acknowledges constitutes newly-discovered evidence, is such that there is a reasonable probability that if a jury heard of Shaibani's misrepresentation of his credentials, the outcome at trial would have been different. Because we determine that Plude is entitled to a new trial on the last basis, we do not consider his first two contentions.

Although Plude did not object to Shaibani being admitted as an expert at trial, once he discovered that Shaibani lied about his teaching post at Temple University, he objected to Shaibani's admission as an expert. In his post-conviction motion, Plude argued that Shaibani was no longer qualified to testify to the mechanics of the human body.

A defendant's due process rights are violated when the newly-discovered evidence is evidence that the government knew about, but did not disclose. Giglio v. United States, 405 U.S. 150 (1992); Brady v. Maryland, 373 U.S. 83 (1963).

The concurring opinion suggests that our opinion may be read to grant a new trial to a defendant as a matter of course whenever an expert witness falsely represents his or her credentials. See Justice Ziegler's concurrence, ¶¶ 90, 97. We do not create such a per se rule.