This appeal arises from the decision of the Kansas City, Missouri, Board of Police Commissioners (“the Board”) to suspend Officer Jeffrey Lagud for misconduct concerning the collection of a urine sample. Officer Lagud appealed. Upon review, we find no error and affirm the Board’s decision.
Background
On September 10, 2000, Officers James Carmody and Jason Crump arrested James Russell on suspicion of driving under the influence. At the time of his arrest, Mr. Russell could not stand on his own and could not perform any of the field sobriety tests. Mr. Russell was then transported to the Kansas City Police Department’s Center Zone Station. Upon arrival, Officer Carmody asked a Drug Recognition and Evaluation (DRE) officer to conduct a drug and alcohol evaluation. Officer Jeffrey Lagud responded and, with the help of Officer Larry Bewick, conducted a number of tests to determine the cause of Mr. Russell’s impairment. Officer Lagud then asked Officer Carmody to help him obtain a urine sample from Mr. Russell.
The two officers escorted Mr. Russell to a urinal located between the eastern wall of the holding cell and a four foot high privacy wall. As the sample was collected, Mr. Russell was facing the urinal with his hands handcuffed behind his back, and Officer Lagud was reaching over the privacy wall holding the sample cup to collect the urine. Officer Carmody was standing behind and to the side of Mr. Russell, supporting Mr. Russell because he was fading in and out of consciousness and having difficulty keeping his balance. Officers Carmody and Lagud have differing accounts as to what occurred during the collection of the urine sample.
According to Officer Lagud, he held the specimen cup in his left hand. Using his right hand, he unbuttoned and unzipped Mr. Russell’s pants, grasped the pants at Mr. Russell’s right hip and pulled them partially down, then grasped the underwear at the same place and pulled them down to expose Mr. Russell’s penis. Officer Lagud then switched the specimen cup to his right hand, instructed Mr. Russell to begin urinating, and leaned over the privacy wall to collect the sample. Once the sample had been obtained, Officer Lagud placed the cap on the cup and waited for Mr. Russell to finish urinating. After Mr. Russell had finished, Officer Lagud grasped the right side of Mr. Russell’s underwear and pulled them back up. He then pulled up Mr. Russell’s pants. Officer Lagud maintained that he never touched Mr. Russell’s penis during this process.
Two days after Mr. Russell’s arrest, Officer Carmody informally discussed the procedures Officer Lagud had used to collect Mr. Russell’s urine sample with Sergeant Carl Abraham, telling him that Officer Lagud had held Mr. Russell’s penis while collecting the urine sample. Sergeant Abraham directed Officer Carmody to complete an internal statement, or “191,” regarding the incident. Officer Carmody did so on September 14, 2000, in which he wrote:
Upon the request of a urine test Crump stood the subject up and began to remove the handcuffs at which time Lagud told Crump to “leave the cuffs on.” La-gud then escorted the subject into a holding cell and asked me to follow. Once at the toilet in the holding cell I stood behind the subject expected La-gud to tell me when he was ready for me to remove the handcuffs, however Lagud just unbuttoned and unzipped the subject’s pants then removed his penis from *288his underwear and instructed him to begin urinating into a specimen container being held in Lagud’s free hand. When the subject had filled the container Lagud aimed the subject’s penis in the toilet allowing him to continue urinating before returning the subject’s penis back into his underwear and asking me to re-zip and re-button the subject’s pants while he secures the collected sample.
Officer Carmody’s statement was forwarded to Officer Lagud’s supervisor, Sergeant Kim Hannan, to determine whether such actions were appropriate. Sergeant Han-nan conducted an investigation into the incident, including a reenactment. She initially recommended that Officers Carmody and Lagud be given polygraph examinations, but when she was told that no polygraphs would be given, she recommended an internal investigation be initiated.
An internal investigation ensued, and a detective interviewed Officers Carmody and Lagud, as well as Mr. Russell, over the next several months. Officer Lagud consistently maintained that he never touched Mr. Russell’s penis at any time the night of Mr. Russell’s arrest. Officer Carmody also answered questions consistently with his 191. After the internal investigation had been completed, Sergeant Hannan reviewed the file and conducted another reenactment of the events. She concluded that Officer Carmody had not been in a position to see Mr. Russell’s groin area during the collection of the urine sample.
After reviewing the internal investigation file and the recommendations from Sergeant Hannan and others in the chain of command, then-Chief of Police Richard Easley filed charges and specifications with the Board requesting Officer Lagud’s termination. Officer Lagud was charged with misconduct for violating department policy by obtaining a urine sample by grabbing and holding an arrestee’s penis and then denying he had done so.
Both Officers Carmody and Lagud were eventually given polygraph examinations. An examiner with the police department conducted Officer Carmody’s examination and found that Officer Carmody was not deceptive in his responses. Officer La-gud’s polygraph examination was conducted by an independent examiner, chosen by Officer Lagud, who found that Officer La-gud was not deceptive throughout the testing process. This examiner reviewed the results from Officer Carmody’s polygraph, and while the examiner stated it was his belief that Officer Carmody was deceptive as to whether he saw Officer Lagud hold Mr. Russell’s penis during the collection of the urine sample, the examiner also acknowledged that both examiners had been trained under different methodologies, and he simply had a different opinion as to the results.
At the hearing before the Board, Officer Carmody conceded that he did not actually see Officer Lagud initially remove Mr. Russell’s penis from his pants. However, Officer Carmody stated that while he may not have seen Officer Lagud initially remove Mr. Russell’s penis from his underwear, he did see Officer Lagud hold it while collecting the urine sample. Officer Carmody explained that he was surprised Officer Lagud had begun to take the sample without requesting Mr. Russell’s hands be uneuffed, so Officer Carmody repositioned himself to see what was occurring. He stated that he saw Officer Lagud holding the sample container in one hand and Mr. Russell’s penis in the other, and that when the container was full, Officer Lagud allowed Mr. Russell to finish urinating. Officer Carmody stated that when Mr. Russell was finished, Officer Lagud *289“shook” Mr. Russell’s penis and placed it back inside Mr. Russell’s underwear.
Mr. Russell testified before the Board that during the collection of the urine sample, Officer Carmody stood behind him, and another officer touched his penis. He was unable to describe the appearance of the officer who took the sample, and upon cross-examination by Officer Lagud, Mr. Russell invoked the Fifth Amendment and refused to answer questions about his drug use and his ability to perceive on the night in question.
Officer Lagud denied that he had touched Mr. Russell’s penis. He testified that he pulled down Mr. Russell’s pants and underwear, placed the sample container in front of Mr. Russell’s penis, and instructed him to urinate.
The Board did not accept Officer La-gud’s account. Although Police Chief Eas-ley had argued for termination, the Board ordered that the appropriate remedy was suspension without pay up to the date of the hearing, which effectively reinstated Officer Lagud.
Officer Lagud appealed to the Circuit Court of Jackson County, which overturned the Board’s decision. The Board then appealed to this Court, which affirmed the decision of the Board. The case was transferred to the Supreme Court, which reversed, holding that Mr. Russell’s testimony, which the Board initially considered, was inadmissible. The Supreme Court remanded the case so the Board could reweigh the evidence without Mr. Russell’s testimony.
Upon remand, the Board conducted oral arguments, reviewed previous arguments of both parties, and considered the record without Mr. Russell’s testimony. The Board again concluded that Officer Lagud had violated department policy and that suspension was the appropriate action. The Board stated that it “considered testimony from police officers Lagud, Carmo-dy, Crump, Bewick [a DRE officer], and Stewart [a DRE instructor] in making its findings. The Board also considered testimony from Sergeants Abraham, Hannan and Chief Easley.” Officer Lagud appealed to the Circuit Court of Jackson County, which reversed the Board’s decision, finding that the Board “singularly relied upon” Officer Carmody’s testimony and that Officer Carmody’s testimony was contradictory and did not provide substantial competent evidence to support the Board’s ruling. This appeal followed.
Standard of Review
In an appeal from an administrative action, we review the administrative agency’s decision, not the decision of the circuit court. TAP Pharm. Prods. Inc. v. State Bd. of Pharmacy, 238 S.W.3d 140, 141 (Mo. banc 2007). Appellate review of an administrative decision is governed by Section 536,140.2, RSMo 2000, which authorizes a court to determine whether the action of an administrative agency:
(1) Is in violation of constitutional provisions;
(2) Is in excess of the statutory authority or jurisdiction of the agency;
(3) Is unsupported by competent and substantial evidence upon the whole record;
(4) Is, for any other reason, unauthorized by law;
(5) Is made upon unlawful procedure or without a fair trial;
(6) Is arbitrary, capricious or unreasonable;
(7) Involves an abuse of discretion.
If there is sufficient competent and substantial evidence to support the administrative agency’s decision, the decision will be upheld. White v. St. Louis Teachers *290Union, Div. of Employment Sec., 217 S.W.3d 382, 388 (Mo.App. W.D.2007). In determining whether there is competent and substantial evidence to support a decision, a court must examine “whether the award is contrary to the overwhelming weight of the evidence.” Hampton v. Big Boy Steel Erection, 121 S.W.3d 220, 222-23 (Mo. banc 2003). “An award that is contrary to the overwhelming weight of the evidence is, in context, not supported by competent and substantial evidence.” Id. at 223.
In reviewing the Board’s decision, we defer to the Board’s determinations regarding “weight of the evidence and the credibility of witnesses.” White, 217 S.W.3d at 388. In addition, if the Board “has reached one of two possible conclusions from the evidence, reviewing authority will not reach a contrary conclusion even if it could reasonably do so.” Id.
Analysis
Officer Lagud asserts that the Board erred in finding Police Chief Easley met his burden of proving the charges against him in that such a finding was not supported by competent and substantial evidence on the record as a whole. In his first point, Officer Lagud contends that the Board erred in relying solely on Officer Carmody’s testimony. In his second point, he argues that the Board erred in dismissing other evidence that conflicted with Officer Carmody’s testimony. We will address Officer Lagud’s two points together.
Substantial evidence is defined as “ ‘evidence which has probative force on the issues, and from which the trier of facts can reasonably decide the case.’ ” White, 217 S.W.3d at 388 (quoting Brown v. Div. of Employment Sec., 947 S.W.2d 448, 452 (Mo.App. W.D.1997)). In his testimony before the Board, Officer Carmody admitted that he did not actually see Officer Lagud reach into Mr. Russell’s pants and take out his penis. However, he unequivocally stated that he did see Officer Lagud holding Mr. Russell’s penis in one hand and the specimen cup in the other. Officer Carmody further testified that after Mr. Russell finished urinating, Office Lagud “shook” Mr. Russell’s penis and placed it back inside Mr. Russell’s underwear. The Board relied on this testimony in reaching its conclusion, stating in its Findings of Fact that “Carmody observed Lagud holding Russell’s penis with Lagud’s left hand and the specimen container in his right hand while Russell urinated into the specimen container.” Officer Lagud points to Officer Carmody’s prior written statement in arguing that Officer Carmody’s testimony is contradictory and cannot qualify as substantial evidence.
While it is true that trial' testimony that contradicts itself does not constitute substantial evidence, prior statements that are simply inconsistent with testimony at a hearing are to be taken into account by the fact-finder judging a witness’s credibility. Lagud v. Kansas City Bd. of Police Comm’rs, 136 S.W.3d 786, 796 (Mo. banc 2004). Officer Carmody’s internal written statement, the 191, was a prior statement written simply as an internal memorandum of the night’s events and the procedures used. In his prior statement, Officer Car-mody stated that “Lagud just unbuttoned and unzipped the subject’s pants then removed his penis from his underwear.” On cross-examination before the Board, however, Officer Cai'mody testified as follows:
Q: Did you tell investigator Dennis Coates that you observed Officer Lagud unzip and unbutton Mr. Russell’s pants?
A: I don’t know if I told him that. Apparently I assumed that that’s how Mr. Russell’s penis was extracted from his underwear.
*291Despite this inconsistency, in no way did Officer Carmody’s testimony before the Board contradict itself. The only variation was between Officer Carmody’s prior statement and his testimony before the Board. This inconsistency may affect Officer Carmody’s credibility, but it does not affect whether his testimony constitutes substantial evidence. Furthermore, while Officer Carmody did concede that he assumed Officer Lagud reached into Mr. Russell’s pants to remove his penis, Officer Carmody never wavered on what the Board found to be crucial evidence: that Officer Carmody saw Mr. Russell’s penis in the hand of Officer Lagud. On direct examination before the Board, Officer Car-mody testified as follows:
Q: Did you ever reposition yourself where you could see the front of Mr. Russell?
A: Yes, sir.
Q: And how did you do that?
A: Just simply I held onto the handcuffs or his hands in the handcuffs and just scooted around to the side.
Q: Okay. Did you then observe Mr. Russell’s groin area?
A: Yes, I did.
Q: And did you observe anybody holding or touching Mr. Russell’s penis?
A: Yes, I did.
Q: And who did you observe do that?
A: Officer Lagud had a hold of Mr. Russell’s penis.
Despite this clear explanation, Officer La-gud argues the inconsistency between Officer Carmody’s prior statement and his hearing testimony proves Officer Carmo-dy’s testimony is unreliable as probative evidence. It is within the Board’s discretion, however, to believe or disbelieve the evidence before it. White, 217 S.W.3d at 388.
Officer Lagud asserts in his appellate brief that if Officer Carmody “had actually witnessed Officer Lagud touch Mr. Russell’s penis, it seems likely that he would have either immediately stopped Officer Lagud or informed a supervisor. Instead, he never mentioned it to anyone until two days later.” The hearing record reveals, however, that Officer Carmody’s partner, Officer Crump, testified that he and Officer Carmody discussed the procedures used to obtain the urine sample the night of Mr. Russell’s arrest. Officer Crump stated that “Officer Carmody commented to me the manner in which the urine specimen was collected along the lines that it was odd.... We collectively decided that, you know, perhaps that was maybe a process DRE or ASAP officers use that we just weren’t familiar with.” When asked what he understood that process to be, he stated that he understood Officer Lagud held Mr. Russell’s penis while collecting the urine sample. He testified that Officer Carmody told him this the night Mr. Russell was arrested.
Officer Lagud also contends that the Board dismissed any evidence that contradicted the version of events testified to by Officer Carmody. This contention is meritless. The Board heard testimony from multiple law enforcement officers and was presented with two different accounts of what happened the night of Mr. Russell’s arrest. The Board stated that it considered this testimony and reached a conclusion based on the evidence presented. “If evidence before an administrative body would warrant either of two opposed findings, we are bound by the administrative determination and it is irrelevant that there is evidence to support a contrary finding.” Cochran v. Bd. of Educ. of Mexico Sch. Dist. No. 59, 815 S.W.2d 55, 59 (Mo.App. E.D.1991). There was evidence to support the Board’s determination, and *292as a result, we must uphold the Board’s findings. See Trusler v. Tate, 941 S.W.2d 794, 797 (Mo.App. W.D.1997).
Officer Lagud also claims that Officer Hannan’s findings were never challenged or disputed, and as such, her testimony cannot be disregarded. While it is true that unimpeached or undisputed evidence cannot be disregarded unless an administrative agency makes a specific finding that such evidence is incredible or unworthy of belief, Stevinson v. Labor & Indus. Relations Comm’n of Mo., Div. of Employment Sec., 654 S.W.2d 373, 374-75 (Mo.App. S.D.1983), this rule is inapplicable here. Officer Hannan’s testimony was disputed — by the testimony of Officer Car-mody. Officer Lagud argues there was extensive testimony before the Board supporting his version of events but that the Board chose only to believe Officer Carmo-dy’s testimony. He cites Yoos v. Jewish Hospital of St. Louis, 645 S.W.2d 177, 185 (Mo.App. E.D.1982), which states that the contradictory testimony of a single witness does not qualify as substantial evidence. However, testimony is not contradictoiy if it is merely inconsistent with a previously written statement, as is the case here. See Lagud, 136 S.W.3d at 796.
A 2001 case before this Court provides guidance on this issue. In Grace v. Mo. Gaming Comm’n, 51 S.W.3d 891, 897-98 (Mo.App. W.D.2001), the appellant argued that the administrative agency’s findings against him were unsupported by competent and substantial evidence. One of the appellant’s employees provided the evidence against him. The appellant argued that the testimony was from a disgruntled employee and was thus so incredible that it could not be deemed substantial evidence. In that case, we found: “The [Commission] is entitled to weigh the credibility of testimony received and believe or disbelieve all or part of any witnesses’ testimony. Obviously, the Commission believed [the employee] and not [the appellant], The Commission’s finding ... is supported by competent and substantial evidence.” Id. at 898 (quotations and citations omitted). Quite simply, if evidence before an administrative agency has any probative force on an issue and can aid the agency in deciding the case, it constitutes substantial evidence, and under the standard of review, we must uphold the agency’s decision. White, 217 S.W.3d at 388.
Furthermore, Officer Lagud actually concedes that the Board did consider testimony other than that of Officer Carmody in making its determination. He argues, however, that the Board only relied on testimony other than that of Officer Car-mody for non-crucial issues. He contends that on the issue of whether Officer Lagud held Mr. Russell’s penis, the Board relied solely on Officer Carmody’s testimony. Despite Officer Lagud’s assertions, it is nevertheless within the Board’s discretion to believe or disbelieve the evidence before it. Id. The Board chose to believe the testimony of Officer Carmody.
Officer Lagud contends that the Board’s findings were insufficient in that they failed to identify specific evidence undermining Officer Lagud’s version of events. This argument is disingenuous. In its findings, the Board stated that it considered testimony from numerous individuals in reaching its conclusion. The Board is not obligated to further defend its reasoning. Credibility of witnesses and the weighing of evidence are functions within the discretion of the Board, id., and the Board exercised its discretion in finding Officer Carmody’s testimony to be credible. Officer Carmody testified that he shifted his position to see what was occurring during the collection of the urine sample, and he stated that he saw Officer Lagud holding Mr. Russell’s penis. Al*293though there was various testimony regarding the incident, the evidence conflicting with Officer Carmody’s testimony was not so overwhelming as to render the Board’s decision as erroneous. Furthermore, despite whatever inconsistencies Officer Lagud may argue, Officer Carmody’s testimony had probative value and was evidence from which the Board could reach its conclusion. Thus, there was competent and substantial evidence to support the Board’s decision.
While the dissent sets forth at great length and in painstaking detail the procedural and factual history of this case in support of its argument that the Board’s ruling was against the weight of the evidence, many of the facts set forth by the dissent are not relevant to the issue before this court: whether, when weighing the evidence as a whole, substantial evidence was presented from which the Board could conclude that Officer Lagud held Mr. Russell’s penis in his hand. Officer Carmody did assume Officer Lagud removed Mr. Russell’s penis from his pants, but this was a logical assumption based on what Officer Carmody did see: Mr. Russell’s penis in Officer Lagud’s hand. Officer Carmody never wavered on this key point.
The decision of the Board is affirmed.
HARDWICK, J., Concurs.
ELLIS, J., Dissents in separate opinion.