delivered the opinion of the court:
Defendants appeal from the order of the circuit court reversing the board’s order discharging plaintiff from his employment as a patrolman with the city police department. They contend that the court erred in reversing the board’s decision. We agree.
After an extensive evidentiary hearing, the board found that on 12 separate occasions plaintiff falsely represented that he was ing for two different employers at two different places during the same period of time and that on 10 of these occasions, plaintiff was on two payrolls for the same period of time and was being paid on the basis of those two payrolls.1 The evidence in support of those findings is discussed below.
The board determined that by this conduct, plaintiff committed the criminal offenses of theft and attempted theft, violated departmental rules requiring compliance with laws and regulations and forbidding unbecoming conduct, and, in one instance, disobeyed á general departmental order by leaving his assigned post without permission. The board decided that plaintiff’s activities constituted a substantial shortcoming which rendered his continuance in employment as a patrolman detrimental to the discipline and efficiency of the service and good cause for no longer being employed as a member of the police department. Accordingly, the board ordered plaintiff’s employment terminated immediately.
On administrative review, the circuit court reversed. The court found that the board’s decision was unconstitutional and illegal, that it violated due process, and that it was against the manifest weight of the evidence. In our judgment, the record does not support these findings and although not all of the court’s criticisms of the proceedings require individual comment, we shall address the principal ones.
The Amendment to the Charges
A 10-count statement of charges was filed with the board on January 25, 1985. On February 2 an amended statement of charges, adding five counts, was filed. On February 26, the date scheduled for the commencement of the evidentiary hearing, the chief of police moved to file a second amended statement of charges. The proposed amendment did not add any new charges but merely made minor *280changes in the charges already on file.2 There was nothing improper in the board’s decision to permit the second amended statement of charges to be filed and plaintiff failed to demonstrate any prejudice because of the amendment. See Giampa v. Civil Service Com. (1980), 89 Ill. App. 3d 606, 611, 411 N.E.2d 1110.
The circuit court’s finding that plaintiff was forced to proceed with the evidentiary hearing only moments after receiving the amended charges is contradicted by the record. Plaintiff’s attorney acknowledged that he had received notice of the proposed changes four days earlier and expressly declined the board’s offer of a continuance to prepare a defense to the second amended statement of charges because of the board’s decision to continue plaintiff’s suspension without pay during the pendency of the hearing.
The Board’s Authority to Suspend Plaintiff Without Pay
The court stated its belief that Thomas McGuire, counsel for the board, improperly advised the board that it had the legal authority to suspend plaintiff without pay for several successive 30-day periods while the administrative hearing was pending.3 We note, however, that in McCoy v. Kamradt (1985), 136 Ill. App. 3d 551, 483 N.E.2d 544, the court construed section of the Illinois Municipal Code (Ill. Rev. Stat. 1983, ch. 24, par. to permit a board of fire and police commissioners to suspend an employee without pay for more than 30 days during the pendency of a hearing. (McCoy v. Kamradt (1985), 136 Ill. App. 3d 551, 559-60. See also People ex rel. Cotter v. Conlisk (1974), 17 Ill. App. 3d 346, 347-48, 308 N.E.2d 1.) That case is dispositive of plaintiff’s argument that the board lacked authority to suspend him without pay for more than 30 days prior to its final decision.
The 1935 Rules
The circuit court found that the rules and regulations under which the board operated (first adopted in 1935) were deficient because they did not specify the manner in which the administrative *281hearing would he conducted. We note, however, that one of them, Rule 39, requires all charges to be set forth in writing, detailing the nature and character of the offense, and gives the accused the right to defend himself. Although the rules are otherwise silent regarding the procedure to be followed at a disciplinary hearing, the failure to adopt any rules governing dismissal proceedings does not constitute cause for reversal, unless prejudice is demonstrated. (Westby v. Board of Fire & Police Commissioners (1977), 48 Ill. App. 3d 388, 391-92, 362 N.E.2d 1098.) Plaintiff did not show how he was prejudiced by the board’s failure to adopt more comprehensive rules.
On February 2, 1985, more than three weeks before the eviden-tiary hearing began, the board, acting through its counsel, advised plaintiffs attorney that the hearing would be conducted in accordance with section of the Illinois Municipal Code (Ill. Rev. Stat. 1985, ch. 24, par. and the cases interpreting that provision. On February 13 he acknowledged receipt of the board’s rules and regulations and on February 26 he protested that those rules failed to specify the manner in which the administrative hearing would be conducted. Prior to that date, he had served the board with a motion asking that it inform him “of the procedural and evidentiary rules to be followed during the course of the hearing.”
In a letter dated February 22, 1985, and sent to counsel for both parties, the board’s attorney reiterated what he had said on February 2 and explained in greater detail the procedural and evidentiary rules that would be followed. Although plaintiff’s attorney denied that he had received this letter, when the contents thereof were explained to him on February 26 he voiced no dissatisfaction with the guidelines McGuire had prepared for the hearing.
In our judgment, plaintiff was not prejudiced by the board’s failure to adopt comprehensive rules governing the dismissal proceedings. He received the fair and impartial hearing to which he was entitled.
The Role of Counsel for the Board
As we have noted previously, attorney Thomas McGuire acted as counsel for the board. At the outset of the hearing, the chairman announced that McGuire would respond to all objections and motions, unless the board decided otherwise.4 The board at all times retained control over the proceedings and was free to accept or reject Mc*282Guire’s rulings as it saw fit, as McGuire often acknowledged during the proceedings. The circuit court took exception to this procedure, but we are aware of no authority forbidding it, at least where the attorney acts in a fair and neutral manner. (See Ladenheim v. Union County Hospital District (1979), 76 Ill. App. 3d 90, 394 N.E.2d 770; Austin v. Board of Fire & Police Commissioners (1972), 7 Ill. App. 3d 537, 544, 288 N.E.2d 113.) Although the court indicated its belief that McGuire was prejudiced against plaintiff, the record does not appear to support this conclusion.
The board, on McGuire’s advice, granted plaintiffs motion for discovery, his motion to bar the taking of photographs in the hearing room, his motion to exclude witnesses, his motion requesting permission to take the sergeant’s examination, and his motion to prevent police officers from wearing their sidearms while they testified.
McGuire cooperated with plaintiff’s attorney in providing subpoenas; urged reciprocal discovery of names and addresses of all potential witnesses; insisted on compliance with the discovery orders (at one point temporarily barring the testimony of a witness whose name had been misspelled in an answer to discovery) and with the order excluding witnesses; and, on one occasion, ordered the hearing to be continued so that plaintiff’s attorney would have an opportunity to receive and review all documentary evidence the chief of police intended to offer.
McGuire allowed plaintiff to present evidence of alleged bias. He sustained numerous objections made by his attorney and overruled others made by the attorney for the chief of police but he did not personally participate in the examination of any witnesses, except when he was expressly directed to do so by the board,5 and he did not act as prosecutor. Finally, it must be noted that McGuire did not make any recommendations to the board regarding disposition of the charges brought against plaintiff or whether plaintiff should be suspended without pay during the pendency of the hearing.
We have reviewed the entire record of the proceedings and are satisfied that Thomas McGuire conducted himself in a fair and impartial manner as counsel for the board.
The Violation op the Discovery Order
In his motion for discovery, plaintiff requested production of *283all written reports of witnesses. Although the attorney for the chief of police represented, apparently in good faith, that there were no such reports, there was one instance of a writing which consisted of a notation made on the back of a time card from the high school by Captain Kozenczak regarding his surveillance of plaintiff on December 17, 1984. The circuit court’s belief that the writing was never disclosed to plaintiff’s attorney in discovery is refuted by the record, which reveals that the time cards were made available to him during a discovery conference on February 13, 1985, almost two weeks before the hearing began. Although he claimed on February 28 that he was not aware of the notation on the back of the time card, he admitted receiving photostatic copies of both sides of the card on February 27, which was 10 days before Captain Kozenczak testified. Since counsel had more than adequate time to prepare his cross-examination, we are unable to perceive how plaintiff was prejudiced by the alleged discovery violation.
The Investigation into Plaintiff’s Misconduct
Plaintiff was not interviewed by any investigator from the police department before he was formally charged with various acts of misconduct. Although the circuit court criticized Captain Kozenczak, who was in charge of the investigation, for not giving plaintiff the opportunity to respond to the allegations before the chief of police filed formal charges against him, we are aware of no authority mandating such a procedure. (See Klein v. Fair Employment Practices Com. (1975), 31 Ill. App. 3d 473, 482-83, 334 N.E.2d 370 (plaintiff has no constitutional right to participate in the investigation of his charge).)6 Notice to the employee of the improper acts he is alleged to have committed is required before interrogation or before investigation. Fletcher v. Civil Service Com. (1972), 6 Ill. App. 3d 593, 596-97, 286 N.E.2d 130.
Plaintiff had the opportunity to defend himself at the administra*284tive He received notice of the charges and enjoyed a hearing before an impartial tribunal at which he was represented by counsel and was allowed to cross-examine witnesses, present evidence in his own defense, and inspect documentary evidence against him. Generally, this is considered sufficient to insure due process in an administrative proceeding. Ladenheim v. Union County Hospital District (1979), 76 Ill. App. 3d 90, 96, 394 N.E.2d 770.
The court also criticized Captain Kozenczak for not interviewing other police officers who worked as part-time security guards at the high school and the bank and for not preparing written reports of the results of his investigation. However, the court did not explain how plaintiff was prejudiced by these alleged failures.
Plaintiff’s attorney could have interviewed any of these officers or served, them with subpoenas to appear at the hearing. Indeed, plaintiff did call two of these officers to testify for him. Moreover, in light of the substantial reliance the department placed on documentary evidence, the captain’s decision not to prepare written reports of his investigation is understandable. In any event, plaintiff has not demonstrated that the failure to prepare such reports was improper or that he was prejudiced thereby.
The Violations of the Exclusion Order
The circuit court criticized McGuire for not enforcing the witness exclusion order against Lieutenant Scheskie, who sat at the hearing table with counsel for the chief of police during most of the proceedings. We believe that this criticism is unjustified.
When plaintiff’s attorney objected to Scheskie’s presence in the hearing room on February 26, 1985, the attorney for the chief of police indicated that he needed Scheskie’s assistance and did not intend to call him as a witness.8 McGuire then ruled that Scheskie could remain since he was not going to testify. It was not until two days later, on February 28, that plaintiff’s attorney first, indicated that he planned to have Scheskie testify in his own case. (Scheskie was not named as a potential witness by plaintiff prior to the hearing.) He expressed concern that he would be barred from calling Scheskie as a witness if he remained in the hearing room because of the reciprocal exclusion order that had been entered. Although the attorney for the *285chief of police offered to waive any objection, this offer did not satisfy plaintiff’s attorney, who felt that Scheskie’s testimony might be influenced by the testimony of Captain Kozenczak and Sergeant Freitag.9
At plaintiff’s request, the board ordered Scheskie to leave the hearing room when Kozenczak and Freitag testified. Nothing in the report of proceedings indicates that Scheskie violated the exclusion order or suggests that plaintiff’s failure to call him as a witness was attributable to a' violation of that order. We note further that since it was plaintiff’s attorney who intended to call Lieutenant Scheskie as a witness, it was his responsibility to see that the lieutenant did not remain in the hearing room when Captain Kozenczak and Sergeant Freitag testified. Plaintiff cannot base a claim of prejudice on his failure to do so.
The court also expressed the opinion that several witnesses violated the order of exclusion by eavesdropping on the hearing and by discussing their testimony with other witnesses.
Plaintiff’s mother and brother testified that Captain Kozenczak and Sergeant Neil were standing next to the closed double doors of the hearing room where they allegedly could hear the testimony of the witness. They also claimed that after Sergeant Diehl left the hearing room, he discussed his testimony with Lieutenant Kuta and other witnesses who had not yet testified.
Both Kozenczak and Neil denied that they had overheard any witnesses or had discussed their testimony with anyone. Diehl denied that he had discussed his testimony with anyone and Kuta testified that he had discussed his testimony with Diehl and no one else only after both witnesses had testified.10
It was for the board to decide whether there was a violation of the exclusion order or the order forbidding witnesses to discuss their testimony with other witnesses who had not yet testified. We are unable to conclude that the board’s decision denying plaintiff’s motion for a “mistrial” was in error.
Admissibility of the Exhibits
The board admitted into evidence 76 exhibits offered by the chief of police at the hearing. All but four of these exhibits were time cards and signed payroll time sheets from the high school, sign-in *286sheets, work schedules, payroll journals and check registers from the bank, daily reports and daily activity forms from the police department, and cancelled payroll checks from both the school district and the bank. Although the circuit court held that these particular exhibits should have been excluded as inadmissible hearsay, we are unable to agree.11
We have carefully reviewed the record and are satisfied that the attorney for the chief of police laid an adequate foundation for the admission of these documents as business records, past recollection recorded, or written admissions of a party-opponent. (87 Ill. 2d R. 236(a); Bass v. Washington-Kinney Co. (1983), 119 Ill. App. 3d 713, 726-27, 457 N.E.2d 85; Benford v. Chicago Transit Authority (1973), 9 Ill. App. 3d 875, 293 N.E.2d 496; People v. Carter (1979), 72 Ill. App. 3d 871, 876, 391 N.E.2d 427; Stanton v. Pennsylvania R.R. Co. (1961), 32 Ill. App. 2d 406, 411-12, 178 N.E.2d 121.
Other Matters
The circuit court faulted the board for not allowing plaintiff to present and argue a motion for a directed finding at the conclusion of the hearing. The court, however, did not articulate how plaintiff was prejudiced thereby. An administrative body has broad discretion in conducting its hearings (Desai v. Metropolitan Sanitary District (1984), 125 Ill. App. 3d 1031, 1033, 466 N.E.2d 1045), and we find no basis here to conclude that the board abused that discretion, particularly in view of the fact that plaintiff was allowed to give a closing argument which essentially served the same purpose.
We also find no support for the court’s finding that the board forced plaintiff’s attorney to present his closing argument “after 16 straight hours of hearing” and restricted him to only 15 minutes of argument. The record does not reflect how long the board was in session but it does show that plaintiff’s attorney stated that he was prepared to go forward with his argument and did not want a continuance. And, after he complained of the proposed limitation on closing argument, the board, through its .attorney, informed him that he could have, as much time as he needed. Nevertheless, his argument takes up less than 12 pages of transcript in the record.
As part of his defense, plaintiff tried to suggest that the testimony of some of the witnesses may have been influenced by their in*287terest in being named to replace the chief of police, who was retiring, or in currying favor with his expected replacement or with the board. Not only do we see no substance to this suggestion but, even assuming it had some relevance, there was no prejudice where the board’s decision was otherwise supported by ample evidence of plaintiff’s mis-' conduct. Green v. Board of Fire & Police Commissioners (1980), 87 Ill. App. 3d 183, 187-88, 408 N.E.2d 1187.
The Manifest Weight of the Evidence
The circuit court found that the board’s decision was against the manifest weight of the evidence. We disagree.
The findings of fact made by an administrative agency are to be considered “prima facie true and correct.” (Ill. Rev. Stat. 1983, ch. 110, par. A court, on administrative review, should not weigh the evidence to determine where the preponderance lies but should limit its inquiry to ascertaining whether the findings and decision of the agency are against the manifest weight of the evidence. (Collura v. Board of Police Commissioners (1986), 113 Ill. 2d 361, 372-73, 498 N.E.2d 1148.) In order for a court of review to find that an agency’s decision is against the manifest weight of the evidence so as to justify substituting its judgment for the discretion of the board, the court must be able to conclude that all reasonable and unbiased persons, acting within the limits prescribed by the law and drawing all inferences in support of the finding, would agree that the finding is erroneous and that the opposite conclusion is clearly evident. (O’Boyle v. Personnel Board (1983), 119 Ill. App. 3d 648, 653-54, 456 N.E.2d 998.) That an opposite conclusion might be reasonable or that the court might have reached a different conclusion is not adequate to set aside the agency’s decision. (119 Ill. App. 3d 648, 654, 456 N.E.2d 998.) In our judgment, an opposite conclusion is not clearly evident.
The board found that on 12 separate occasions plaintiff falsely represented that he was working for two different employers at two. different places during the same period of time and that on 10 of these occasions, plaintiff was on two payrolls for the same period of time and was being paid on the basis of those two payrolls. These findings were supported by substantial documentary evidence, including time cards and payroll time sheets from the high school, sign-in sheets, work schedules, payroll journals and check registers from the bank, daily reports and daily activity forms from the police department, and cancelled paychecks from both the school district and the bank. There was also evidence of a surveillance that was conducted of plaintiff’s activities on one occasion.
*288Plaintiff’s signature appeared on the time sheets from the high school,12 the sign-in sheets from the bank, and the payroll checks from both. Plaintiff refused to identify his signature on any of these documents. He admitted, however, that his social security number appeared on the time sheets, that his address had been printed on the front of the checks from the bank, and that his bank account number had been written on the back of many of the checks from both the high school and the bank. Although his name and badge number appeared on the daily activity forms which were turned in at the end of each shift at the police department, plaintiff was unable to state whether he had completed any of the forms.
With the exception of the one incident where there had been a surveillance (December 17, 1984), plaintiff could not recall whether he had been scheduled to work or had worked at the police department, the high school, or the bank on any of the dates specified in the charges. Although he generally denied that he had received or had attempted to receive any compensation from either the high school or the bank for time which either he or a substitute he paid had not actually worked,13 plaintiff presented no evidence that anyone substituted for him on any of the dates set forth in the charges. Further, plaintiff never explained why a substitute would not simply punch his own time card and fill in his own time sheet at the high school or sign in and sign out for himself at the security desk located at the bank. Indeed, plaintiff himself testified that when he substituted for another officer at the high school on December 17, 1984, he used his own time card.14
Plaintiff’s defense cannot be reconciled with the documentary evidence, and his generalized denials of wrongdoing and his credibility were discredited by his persistent refusal to identify his signature on more than 40 documents, his inability to recognize other documents that he prepared, and his failure to recall where he was working on any of the dates in question. From our review of the record, we are satisfied that the board’s decision was not against the manifest weight of the evidence.
*289Specific Findings of Fact
Plaintiff argued to the circuit court that the board failed to make specific findings of fact on the record. The board’s findings were properly and adequately set forth in its written. decision discharging plaintiff from the department. There is no requirement that the findings themselves must be made “on the record,” i.e., orally, during the course of the hearing. Shapiro v. Regional Board of School Trustees (1983), 116 Ill. App. 3d 397, 402-03, 451 N.E.2d 1282.
The Denial of Plaintiff’s Petition for Rehearing
Plaintiff also argued that the board improperly denied his petition for rehearing. Although one of the defendants responds that the board had no authority to grant a rehearing (see People ex rel. Olin Corp. v. Department of Labor (1981), 95 Ill. App. 3d 1108, 1112, 420 N.E.2d 1043 (and the cases cited therein)), we need not decide this issue. Even assuming, arguendo, that a rehearing could have been allowed, we note that normally an administrative agency is not required to open up the record and consider new evidence. Lloyd A. Fry Roofing Co. v. Pollution Control Board (1977), 46 Ill. App. 3d 412, 417, 361 N.E.2d 23.
The “new evidence” plaintiff offered in support of his petition consisted of extremely vague representations that several other police officers on the department would testify that they substituted for plaintiff as a security guard on various unspecified dates in 1984. None of this proposed testimony would have contradicted the board’s findings and the petition for rehearing was properly denied. We note further that plaintiff could have subpoenaed these officers to testify at his administrative hearing. See McLean v. Rockford (N.D. Ill. 1975), 404 F. Supp. 191, 198 (and the cases cited therein).
The Sanction of Discharge
Although not discussed in the circuit court’s decision, we shall briefly address the propriety of the sanction of discharge.
An administrative agency’s decision as to whether cause for discharge exists will not be reversed unless it is arbitrary, unreasonable, or unrelated to the requirements of service. (Department of Mental Health & Developmental Disabilities v. Civil Service Com. (1981), 85 Ill. 2d 547, 552, 426 N.E.2d 885.) Here, the board determined that plaintiff committed the criminal offenses of theft and attempted theft, violated departmental rules requiring compliance with laws and regulations and forbidding unbecoming conduct, and, in one instance, disobeyed a general departmental order by leaving his assigned post *290without permission. The board decided that plaintiff’s activities constituted a substantial shortcoming which rendered his continuance in employment as a patrolman detrimental to the discipline and efficiency of the service and good cause for no longer being employed as a member of the police department. (See Brown v. Civil Service Com. (1985), 133 Ill. App. 3d 35, 41, 478 N.E.2d 541.) Accordingly, the board ordered Sheehan’s employment terminated immediately.
We believe that the sanction of discharge was fully warranted by what one of the defendants characterizes as plaintiff’s “continuous pattern and practice of deception of off-duty employers.” Even plaintiff’s attorney conceded in his opening statement to the board that “if my client did what is stated in the allegations there would be sufficient basis to remove him from the department.” It is apparent that a police officer who does not abide by the laws which he has a duty to enforce will impair the discipline and efficiency of the police force. Sufficient cause for plaintiff’s discharge exists regardless of whether other officers in the department may have received different treatment. (Jones v. Civil Service Com. (1979), 80 Ill. App. 3d 74, 76, 399 N.E.2d 256.)15 Upon our review of the record and the board’s findings of fact, we are unable to conclude that the sanction of discharge was arbitrary, unreasonable, or unrelated to the requirements of service.
For the foregoing reasons, we reverse the judgment of the circuit court of Cook County reversing the board’s findings, decisions, and order of discharge.
Reversed.
LORENZ and MURRAY, JJ., concur.