McKinley Dudley, petitioner-appellant, was convicted by a jury in an Indiana state court of aiding a bank robbery for which codefendants Kennis Butler and Rodney Phillips were convicted in the same trial.1 The Indiana Supreme Court affirmed their convictions after reviewing numerous alleged errors.2 Thereafter, Dudley filed this petition for writ of habeas corpus under 28 U.S.C. § 2254. The principal claims Dudley raises in this appeal are that comments by the prosecutor about Dudley’s silence violated his rights under the fifth and fourteenth amendments, and further, that the admission of prejudicial and irrelevant evidence violated his fourteenth amendment rights. We need reach only this latter issue.
I. FACTUAL BACKGROUND
The state charged that four people, Ken-nis Butler, Rodney Phillips, Edward Pointer, and petitioner-appellant McKinley Dudley, along with Cecil Lewis,3 on May 27, 1982, executed an armed robbery of a state bank.
The evidence showed that Pointer, Butler, and Phillips drove a blue Oldsmobile to the bank. Butler and Phillips, armed with hand guns, entered the bank and escaped with $8,835. Pointer waited outside in the car to facilitate their escape. After a high-speed chase, during which Phillips fired at the pursuing police, all three were captured and the stolen money recovered.4
The state’s evidence showed that the participants discussed the robbery several days beforehand in Dudley’s presence, and again at Dudley’s house the day before the robbery occurred. The evidence also showed the other participants obtained guns from Dudley. Another meeting, at*969tended by all participants, was held at a tavern on the day of the robbery. All defendants agreed to split the proceeds of the bank robbery. The state’s evidence further showed that a green Cadillac owned by Dudley was to be used as a switch getaway car, and a blue Oldsmobile belonging to Dudley’s girlfriend was to be used by the three defendants initially to go to the bank. When Pointer, Butler, and Phillips left in the Oldsmobile for the bank Dudley and Lewis drove the Cadillac to the prearranged switch point. Dudley decided when he arrived at the switch point that it was not a suitable place so he and Lewis abandoned the project and drove off toward Gary, Indiana. Dudley was arrested after his girlfriend went to the police station to retrieve her misused Oldsmobile.
Dudley testified in his own behalf, denying any participation in the bank robbery, and explained his contacts with the defendants as resulting merely from an agreement he had made with Lewis to fix a friend’s ear, which just happened to be on the day of the bank robbery.
II. DISCUSSION
Pointer, originally a codefendant who agreed to testify for the state in exchange for a reduced sentence, was called as a state witness against Dudley. The direct examination began by his answering what his name was, where he lived (with his aunt in Gary, Indiana), where his mother lived (in Chicago), and his age (twenty-three).
Immediately after these few preliminary questions, the prosecutor began the inquiry which, with the responses of the witness, constitutes the challenged testimony. Pointer was then asked “how he felt about testifying.” “Nervous” was his response. The prosecutor pursued the subject, asking why he was nervous and what had happened to make him nervous. The witness, Pointer, explained that the prosecutor “kind of upset me this morning.” He then added that he had received some phone calls the night before which were intended for him and his mother. He did not know who made the phone calls. Then came a leading question: “Are you afraid for your girlfriend and your aunt if you testify?” “Yes,” Pointer responded. Upon being asked what he was afraid of, he explained that he was afraid that whoever had made the phone calls might threaten or harm his mother, “or anything.” At sidebar counsel objected to that line of questioning and asked that it be stricken, moving for a mistrial on the basis that the state was trying to prejudice the defendants by linking the anonymous threats to them. There was nothing, counsel argued, to show that the defendants had anything to do with the alleged phone call threats. The prosecutor defended the question as an attempt to explain the demeanor of the witness and how the witness felt about testifying. In reply, defense counsel argued that the prejudicial effect outweighed any potential relevance to Pointer’s demeanor. The prosecutor then added in justification of the testimony that there had been no showing as to who made the phone calls. Defendant’s counsel explained that that was exactly his point, a point which also concerns us.
The trial court denied both the mistrial motion and the motion to strike the testimony. The testimony was allowed to stand.5 The admission of that evidence, petitioner argues, violated his fourteenth amendment protections because the threats admittedly came from an unknown source and were not linked to him or his codefend-ants except by prejudicial innuendo. That argument for the exclusion of the testimony is the same argument which we understand the state to be using in this court to justify its admission. Both parties cannot be correct. Because the threats were not connected in the evidence to any of the defendants, as the state admits, the state claims that the testimony could not be prejudicial to the defendants. In addition, the state argues that the threat evidence was relevant to Pointer’s demeanor on the witness stand. The state further argues that the jury’s interest in understanding the reason for Pointer’s nervousness was not outweighed by the possible prejudicial effect of threatening telephone call evidence. *970The Supreme Court of Indiana found that the trial court did not abuse its discretion by admitting the evidence. Dudley v. State, 480 N.E.2d 881, 900 (Ind.1985). The state supreme court adopted the state’s explanation that the testimony about the anonymous phone calls was necessary to explain Pointer’s “extreme nervousness.” The district judge subsequently found that the Constitution was not implicated by this exchange because it was a very small incident in a fairly lengthy proceeding and did not amount to a denial of fundamental fairness.
There is at least some agreement between the parties as to the standard of review for this issue. As the petitioner recognizes, the admissibility of evidence is generally a matter of state law. United States ex rel. DiGiacomo v. Franzen, 680 F.2d 515, 517 (7th Cir.1982); United States ex rel. Clark v. Fike, 538 F.2d 750, 757 (7th Cir.1976), cert. denied, 429 U.S. 1064, 97 S.Ct. 791, 50 L.Ed.2d 781 (1977). A writ of habeas corpus should issue, however, when an erroneous evidentiary ruling “is of such magnitude that the result is a denial of fundamental fairness.” United States ex rel. Palmer v. DeRobertis, 738 F.2d 168, 170 (7th Cir.), cert. denied, 469 U.S. 924, 105 S.Ct. 306, 83 L.Ed.2d 241 (1984); see also Love v. Young, 781 F.2d 1307, 1312 (7th Cir.), cert. denied, 476 U.S. 1185, 106 S.Ct. 2923, 91 L.Ed.2d 551 (1986); Cramer v. Fahner, 683 F.2d 1376, 1385 (7th Cir.), cert. denied, 459 U.S. 1016, 103 S.Ct. 376, 74 L.Ed.2d 509 (1982). In determining whether a writ should issue, the court must determine “whether the probative value of the evidence outweighs the prejudice to the accused.” Palmer, 738 F.2d at 171; United States ex rel. Durso v. Pate, 426 F.2d 1083, 1086 (7th Cir.1970), cert. denied, 400 U.S. 995, 91 S.Ct. 469, 27 L.Ed.2d 445 (1971).6
Indiana courts have held that a witness’s testimony concerning threats the witness has received when no connection is shown between the defendant and the threats, can amount to an “evidential harpoon.” Keyser v. State, 160 Ind.App. 566, 312 N.E.2d 922, 924 (1974); see also Cox v. State, 422 N.E.2d 357, 360-63 (Ind.App.1981). “[Sjuch evidence becomes so prejudicial to a defendant that no jury could be expected to apply it solely to the question of the credibility of the witness before it and not to the substantial prejudice of the defendant.” Keyser, 160 Ind.App. at 569, 312 N.E.2d at 924. In the Keyser case, the court found the testimony’s prejudicial effect on the defendant to be so great that an instruction to the jury to disregard it was not sufficient to expiate its effect. That error, when combined with others, led the court to reverse and remand the case for a new trial.
In Cox, a witness testified that he had received threats regarding his testimony at trial. Although the people who threatened the witness knew he was testifying against Cox, the defendant, there was no evidence that Cox was responsible for or had knowledge of the threats. The trial judge, noting that evidence of threats generally must be connected to the defendant, ruled that this was not necessary where the witness was confined to prison from the date of the alleged offense until the date of trial. 422 N.E.2d at 361. The appellate court found no support for this exception, and ruled that the testimony should have been excluded. Id. at 361-62. “Since threats tend to show guilty knowledge or an admission of guilt on the part of the defendant, a proper foundation must be laid showing the threats were made either by the defendant or with his or her knowledge or authorization.” Id. “Barring such a showing, the highly prejudicial nature of such testimony requires its exclusion.” Id. at 362.
The Indiana Supreme Court did not mention these prior Indiana appellate court cases in its opinion, nor does the state in its brief in this court. Instead, the supreme court emphasized that the prosecutor made it clear to the trial judge that the testimony was to “explain witness Pointer’s extreme *971nervousness.” 480 N.E.2d at 900. It is difficult for us to detect any “extreme nervousness” from the record. The prosecutor argued to the trial judge only that she should be permitted to explain the “demeanor” of the witness and why the witness was in the condition that he was. Exactly what Pointer’s condition may have been, however, is not described. No clues appear in the record. The prosecutor further argued that her purpose was to explain “just how the witness feels about testifying here.” The feelings of the witness about testifying would ordinarily be of no relevance. The trial judge did not make any observation in the record about the witness’s condition or behavior.
It is also interesting to note that when the prosecutor asked, “What has happened to make you nervous, Eddie?” Pointer’s first response was, “You kind of upset me this morning,” adding only after that, “and I got some phone calls last night.” It appears that Pointer blamed the prosecutor for contributing to his nervousness because of something she allegedly did or said that morning. The prosecutor proceeded with the additional leading question about Pointer’s fears for his girlfriend and aunt. Nothing appears in the record, however, to explain what the prosecutor herself may have said or done to make the witness nervous. The prosecution avoided any explanation of that aspect of the nervousness of the witness.
Going by the record, which is all we have, we find nothing to show nervousness on the part of the witness except the suggestion initiated by the prosecutor’s question about how the witness felt about testifying. The transcript reflects no incoherence, no delay in the witness’s responses to questions. No one requested, for instance, a short recess to give the witness an opportunity to compose himself. He was given no opportunity to settle down, assuming he was unduly nervous. It clearly appears that the prosecutor’s intent was to put the threat evidence before the jury as soon as Pointer took the stand. As soon as the threat evidence was presented there seems to have been no further concern with his nervousness. After Pointer told about the anonymous threats, all seems to have gone well. This record suggests to us the strong possibility that the prosecutor intended to get the threat testimony before the jury under a pretext. Nervousness is not an uncommon condition affecting witnesses. Those natural anxieties, without more, cannot be a means of admitting otherwise prejudicial evidence. A court may attempt in other ways, at least initially, to make it easier for an anxious witness to proceed. Nervousness often quickly dissipates after the first few questions.
In considering the petitioner’s alibi defense, his credibility, because he testified in his own behalf, takes on added significance. Pointer’s threat testimony could only reflect adversely on the petitioner even though the threats were not traced to him or his eodefendants, except by innuendo. The fact that the supreme court decided this and other issues does not end our own inquiry; in reviewing the denial of the petition for a writ of habeas corpus we must consider these issues in their constitutional context. See Shillcutt v. Gagnon, 827 F.2d 1155, 1158 (7th Cir.1987).
The Supreme Court of Indiana found that the defendant was not subjected to “grave peril” by the admission of the testimony. Dudley v. State, 480 N.E.2d at 900. That court had earlier applied the “grave peril” standard in White v. State, 257 Ind. 64, 272 N.E.2d 312, 319-20 (1971). White was convicted of theft. The issue was the prejudice resulting from the brief testimony of a police officer who said he had previously seen the defendant when he was brought into the police station “with reference to an armed robbery case.” 272 N.E. 2d at 313. That robbery case was unrelated to the charge being tried, and the witness had no knowledge of defendant’s alleged involvement with the crime for which he was being tried. The state argued the evidence was only for identification purposes. The trial court struck the testimony, but denied the motion for mistrial. The Supreme Court of Indiana (asking, “Identification of what?”) reversed, concluding that the prejudicial testimony was offered for no other reason than to *972prejudice the jury, a prejudice no instruction could erase. Id. at 319. It had placed the defendant in a position of “grave peril.” Id. at 320.
The situation here is somewhat similar to that in White. The record strongly suggests that the evidence of threats was intended more to prejudice the defendants, including petitioner, than to explain away any nervousness of the witness. We believe that more was at issue in the present case than a mere abuse of discretion as found by the state supreme court. This error appears to us to be of constitutionally significant proportions. When the prejudicial effect of the testimony is weighed against its necessity, even assuming the witness’s nervousness was extreme, which seems to exaggerate the record, we find that the resulting prejudice mandates relief. We need not try to apply the “grave peril” Indiana standard, however, because we find that the trial court’s ruling allowing the testimony to stand “is of such magnitude that the result is a denial of fundamental fairness.” United States ex rel. Palmer v. DeRobertis, 738 F.2d 168, 170 (7th Cir.), cert. denied, 469 U.S. 924, 105 S.Ct. 306, 83 L.Ed.2d 241 (1984). The admission of this threat testimony could not but deprive petitioner of his right to present an alibi defense to a jury free from “evidential harpoons.” We find the error amounts to a violation of the petitioner’s fourteenth amendment right.
We do not believe that this error can be considered harmless beyond a reasonable doubt. Chapman v. California, 386 U.S. 18, 24, 87 S.Ct. 824, 828, 17 L.Ed. 2d 705 (1967); United States ex rel. Savory v. Lane, 832 F.2d 1011, 1016 (7th Cir.1987). The evidence of petitioner’s guilt was impressive but not overwhelming. Savory, 832 F.2d at 1020. In a trial that lasted more than two weeks and involved approximately thirty-three witnesses, only two witnesses, Lewis and Pointer, implicated the petitioner in the robbery. Lewis and Pointer, admitted accomplices testifying in exchange for immunity or dismissal of charges, are inherently dubious witnesses. The strength of their sometimes conflicting testimony does not approach the level required to render this constitutional error harmless.7
Although we find we must differ with the judgments of the Supreme Court of Indiana and the district court on this particular issue, we do so reluctantly and with respect for both courts. Even in close questions, however, we are bound to determine the constitutional issues as we see them. This “evidential harpoon” error, to borrow the words of the Indiana appellate court in a prior case, cannot be considered harmless when it could totally undermine the defense offered. Viewed as a whole, the petitioner’s trial was constitutionally unfair. The petitioner deserves the writ, but he also deserves to be retried.
Reversed and remanded for the entry of an order granting the petition for a writ of habeas corpus provided the State of Indiana does not retry petitioner within 120 days.
APPENDIX
The opening portion of the direct testimony of Edward Pointer, Transcript pages 0618-22:
*973A Edward Pointer.
Q Do you have a nickname?
A Eddie.
Q Any other nickname?
A No.
Q Where do you live, Eddie?
A 560 Pierce in Gary, Indiana.
Q Who do you live there with?
A My aunt.
Q How long have you lived with your aunt?
A All my life.
Q Where is your mother?
A She’s there in Chicago.
Q And your father?
A I don’t know.
Q How old are you, Eddie?
A 23.
Q Eddie, how do you feel about testifying here today?
A Nervous. Really don’t feel up to it.
Q Why not?
A Just nervous.
Q Are your aunt and your girlfriend in the courtroom here today?
A Yes.
Q Eddie, you are going to have to talk up a little louder so that the jury and everyone can hear what you say, okay?
A Yes.
Q Why don’t you feel up to testify here today?
MR GERMANN: Objection, Your Honor. The question has been asked and answered.
THE COURT: Sustained.
MS. VAIDIK: Q Why are you nervous, Eddie?
A Just nervous; that’s all, period.
Q What has happened to make you nervous, Eddie?
A You kind of upset me this morning, and I got some phone calls last night.
Q Were those phone calls from me?
A No, they was for me and my mother.
Q Do you know who made those phone calls?
A No.
Q Are you afraid for your girlfriend and your aunt if you testify?
A Yes.
Q What are you afraid of?
A Whoever calling.
Q I couldn’t hear what you said.
A Whoever called.
Q What are you afraid of?
A May threat or harm my mother or anything.
MR. GERMANN: Your Honor, may we approach the bench?
THE COURT: Yes.
(Whereupon the following discussion was had at the bench outside the hearing of the jury:)
MS. VAIDIK: I am not going to go any further with this line of questioning as to the content of the conversation, and that is the end.
MR. GERMANN: Your Honor, at this time I am going to move for mistrial. It is apparent that the State of Indiana is attempting to introduce evidence that threats were made by and on behalf of the Defendants in this case. There has been no foundation shown that any of these people were directly or indirectly related in that. The inference is clear that is exactly what has happened. I ask that the testimony be stricken, that the jury be admonished to disregard it, and on behalf of McKinley Dudley, I move for mistrial.
MS. RUDASICS-HARPER: On behalf of Defendant Butler, I would join in that motion.
MS. TAPOCSI: On behalf of Rodney Phillips, I would join in that.
MS. VAIDIK: I think it is plausible to go to the demeanor of the witness, why he is in the condition that he is right now. I think that is something the jury should know. We have not gone into any threatening communications or any such thing, just how the Defendant feels about testifying here.
*974MR. GERMANN: Your Honor, that maybe true, but the prejudicial effect of that certainly outweighs any potential relevance it has to this man’s demeanor.
MS. VAIDIK: There has been no implication made whatsoever as to who made those phone calls or what, in fact—
MR. GERMANN: That is the point, Your Honor.
MS. VAIDIK: He says he doesn’t know.
THE COURT: Motion for Mistrial will be denied. I will allow the testimony to stand. I will not — if anything further needs to be done on that on cross-examination, fine, but motions will be denied.
(Which concluded the discussion held at the bench.)
. Dudley received a twenty-year sentence for aiding the bank robbery and a thirty-year sentence for being a habitual offender, to be served consecutively. Dudley’s codefendants each received twenty-year sentences for bank robbery plus four-year sentences for criminal recklessness.
. Dudley v. State, 480 N.E.2d 881 (Ind.1985).
. Cecil Lewis, although he admitted participation, avoided being charged as he was given immunity and thereafter cooperated with the prosecution and implicated Dudley.
. 480 N.E.2d at 889.
. The transcript of this portion of the trial is attached as an appendix.
. This standard is parallel to the standard of review in a direct appeal. Durso, 426 F.2d at 1086.
. The petitioner also challenges the propriety of a subsequent exchange between the prosecutor and the witness Pointer. Pointer, on direct examination, was questioned about when he first heard about the contemplated bank robbery. Pointer answered that it was when he was riding alone with Dudley down a particular route referred to as “12."
Q What was your purpose in going down 12 that day?
A Me and Kenny [ (codefendant Kennis Butler) ] was going to rob a liquor store out there.
Defense counsel immediately objected and moved for a mistrial. The motion was denied, but the judge struck the testimony and admonished the jury to disregard the last answer.
The state argues that, although petitioner was in the car at the time, the conversation did not pertain to him. It involved Pointer and another codefendant, but did not directly implicate Dudley. We believe that the trial judge’s efforts to cure the possibly prejudicial effect of this testimony in isolation were sufficient to eliminate any prejudice to petitioner resulting from his association with the other two defendants. However, this testimonial episode did not add to the fairness of this trial.