*120OPINION
By the Court,
Mowbray, C. J.:Appellant Benito Anaya seeks review of the district court’s *121order revoking his probation. Anaya contends that the district court erred both in finding that his waiver of his preliminary hearing constituted a waiver of his due process rights at the later revocation hearing and in admitting the multiple hearsay testimony of his probation officer for the purpose of establishing a substantive violation of the terms of his probation. We agree and therefore reverse and remand to the district court for a new revocation hearing.
In July, 1977, Anaya was placed on probation for a term not to exceed five years. In addition to other conditions of probation, he was ordered to enter and complete a drug treatment program approved by the Department of Parole and Probation, to maintain a blood alcohol level of below .10, and to submit to search by any probation officer on request. Appellant was then placed by the Treatment Alternative to Street Crime (TASC) program in an approved Veterans Administration drug rehabilitation center in Brentwood, California. Appellant later requested permission of his counselor to return to Las Vegas to seek another program. He returned to Las Vegas and reported to TASC, which placed him in a rehabilitation program at Fitz-simmons House in Las Vegas. He reported to the probation department, registered as an ex-felon, and reported to probation officials that he had obtained a job. On November 7, 1977, appellant was arrested by North Las Vegas police for driving under the influence, a violation of NRS 484.379. The State moved to revoke Anaya’s probation, alleging violations of his probation with respect to intoxicants, failure to cooperate with probation authorities, failure to conform his conduct to the law, and failure to complete a drug rehabilitation program.
A probation revocation hearing was held on January 24, 1978. The State’s principal witness was appellant’s probation officer, David Hill, who testified that appellant had waived his right to a preliminary inquiry, under NRS 176.216. He further testified that, according to an arrest report, appellant’s blood alcohol level at the time of his arrest on November 7 was .220. The arrest report referred to by Hill was not entered into evidence; nor were the arresting officers called to testify by the State, although they had been present on previous occasions when the revocation hearing had been continued. In response to Anaya’s constitutional and statutory objections to Hill’s testimony, the district court ruled that the confrontation rights granted by NRS 176.217(2)(d) and by the United States Constitution had been waived by appellant when the preliminary inquiry was waived. At the close of the hearing, appellant’s probation was revoked, and this appeal was taken.
*122Parole and probation revocations are not criminal prosecutions; the full panoply of constitutional protections afforded a criminal defendant does not apply. See Gagnon v. Scarpelli, 411 U.S. 778 (1973); Morrissey v. Brewer, 408 U.S. 471 (1972). Revocation proceedings, however, may very well result in a loss of liberty, thereby triggering the flexible but fundamental protections of the due process clause of the Fourteenth Amendment. Id. Due process requires, at a minimum, that a revocation be based upon “verified facts” so that “the exercise of discretion will be informed by an accurate knowledge of the [probationer’s] behavior.” Morrissey, 408 U.S. at 484.
In order to insure that this constitutional standard is achieved and to offer guidance to the states in structuring their respective revocation procedures, the United States Supreme Court, in Morrissey and Gagnon, outlined the minimal procedures necessary to revoke probation or parole. A preliminary inquiry, to determine whether there is probable cause to believe that the probationer violated the conditions of his or her probation, is required, at which the probationer must be given notice of the alleged probation violations, an opportunity to appear and speak on his own behalf and to bring in relevant information, an opportunity to question persons giving adverse information, and written findings by the hearing officer, who must be “someone not directly involved in the case.” Morrissey, 408 U.S. at 485-87. If probable cause is found, the probationer is entitled to a formal revocation hearing, less summary than the preliminary inquiry, at which the same rights attach, Gagnon, 411 U.S. at 786, before a “neutral and detached” hearing body, Morrissey, 408 U.S. at 489. The function of the final hearing is to determine not only whether the alleged violations actually occurred, but whether “the facts as determined warrant revocation.” Id. at 480, 488; see Gagnon, 411 U.S. at 790.
These constitutional standards have been codified, in part, in Nevada. See NRS 176.216-.218. NRS 176.217(2)(d) provides that-at the preliminary inqHwy a probationer shall be allowed to “[c]onfront and question any person who has given adverse information on which a revocation of his probation may be based, unless in the opinion of the inquiring officer the person would be subjected to a risk of harm by disclosure of his identity.” The statute is silent, however, as to the standards applicable to the final revocation hearing, which is held before a district judge. NRS 176.221. As noted above, Morrissey and *123Gagnon mandate that the due process protections available at the preliminary hearing apply to the less summary final revocation hearing with equal, if not greater, force. We therefore hold that a probationer has a due process right to confront and question witnesses giving adverse information at the formal revocation hearing which is not foreclosed by negative inference from NRS 176.217 which grants this right at the preliminary inquiry. Cf. Milchem, Inc. v. District Court, 84 Nev. 541, 549, 445 P.2d 148, 153 (1968) (this Court will construe statutes to avoid unconstitutionality whenever possible). In the instant case, the district court determined that, by waiving his right to a preliminary inquiry, appellant had also waived his due process confrontation rights at the final hearing. Since the record does not demonstrate that appellant knowingly and intelligently waived a known right, the district court erred in concluding otherwise. See Johnson v. Zerbst, 304 U.S. 458 (1938).
Having found that appellant had a due process right to confront and question witnesses giving information against him, we must determine whether the use of the probation officer’s multiple hearsay testimony for the purpose of establishing a substantive violation of probation conditions violated that right. The process due a probationer is determined by balancing the strength of the probationer’s interest in confronting and cross-examining the primary sources of the information being used against him against the very practical difficulty of securing the live testimony of actual witnesses to his alleged violation or to his character while on probation. An important factor in this balancing is the purpose for which the information is offered. If evidence is presented, as in the instant case, to establish a substantive violation of a probation condition, the probationer’s interest in questioning the actual source of the information, and thus testing its reliability, is far stronger than if the information relates merely to his general character while on probation. Similarly, the form of the information is important in striking the due process balance: not every use, of course, of hearsay evidence which is reliable runs afoul of the due process clause. See, e.g., United States v. Pattman, 535 F.2d 1062 (8th Cir. 1976); United States v. Miller, 514 F.2d 41 (9th Cir. 1975).
Thus, if an arrest report were introduced, we see no difficulty in considering it as prima facie evidence of the facts it contains. When the accuracy of the facts alleged is challenged *124by the probationer, however, the presumptive reliability of the report when used to establish facts constituting a probation violation becomes more questionable.1 On the other hand, in the more discretionary phase of a revocation proceeding, determining whether revocation is appropriate, a probationer is permitted to introduce evidence, such as “letters, affidavits, and other material that would not be admissible in an adversary criminal trial.” Morrissey, 408 U.S. at 489. We consider this to mean that the procedure due must be flexible enough to allow the probationer to show mitigating circumstances and the prosecutor to show aggravating circumstances with respect to a violation which has been previously established in order to aid the court in determining an appropriate rehabilitative or punitive response to a proven violation. If the probationer wishes to introduce hearsay evidence of his good character while, on probation, for example, no purpose would be served by declining to admit it.
In applying these standards to the instant case, we note that the challenged testimony was offered into evidence to establish appellant’s substantive violation of the conditions of his probation, thus directly implicating appellant’s constitutionally protected liberty interest. The probation officer testified extensively as to the circumstances of appellant’s arrest for drunk driving: the probation officer was allowed to testify that appellant’s blood alcohol level was .220 at the time of the arrest and as to other details of the arrest. The probation officer’s testimony, summarizing the contents of an arrest report, was multiple hearsay: predicated purely upon a recital of what the report said that the arresting officers had observed. Despite the problems of reliability raised by this testimony, the arrest report was *125not introduced into evidence; the arresting officers did not testify at the hearing; nor does the record contain any explanation for their absence. Moreover, there is no indication in the record that either the probation officer or the probationer even had a copy of the report. Neither the district court, the probationer, nor this Court on review could have any means of testing the accuracy or reliability of the facts recited in the report itself or of the probation officer’s recollection of them. Under these circumstances, where the probationer’s liberty interest is substantial and the State’s interest in admitting such multiple hearsay testimony rather than more reliable evidence is slight,2 we must conclude that the probationer’s due process right to confront and question his accusers was violated.
In conclusion, we hold that the admissibility of evidence at a probation revocation hearing is to be governed by a due process balancing standard. In reaching an appropriate determination, the trial court must exercise its sound discretion after carefully considering the respective interests of the probationer and the State, the purpose for which the evidence is offered, and the nature and quality of that evidence. Under the standard announced today, following Morrissey, Gagnon, and NRS 176.217(2), we conclude that appellant was denied his due process right to a fair revocation hearing. Accordingly, we reverse the order of the district court revoking appellant’s probation and remand the cause for a new revocation hearing.
Gunderson and Batjer, JJ., concur.In Miller, cited above, unauthenticated photostatic copies of court records of a probationer’s subsequent convictions were admitted at a revocation hearing. Tlie court noted that the accuracy and reliability of the copies were not challenged, but, while holding that no due process violation had occurred, the court disapproved the prosecution’s reliance upon such secondary evidence when more reliable evidence, the testimony of the arresting officers, was readily available. 514 F.2d at 43. We observe that on the issue of whether a probation violation has occurred, a court record of a conviction is presumptively far more reliable than an arrest report, which does not involve an adjudication of guilt beyond a reasonable doubt. Similarly, in Pattman, cited above, a probation officer read from an arrest report which named and described the probationer. The probation violation for which revocation was sought, however, was failure to report an arrest, not for the substantive offense charged in the report; and the court considered it for the purpose of showing an arrest. With respect to the issue of whether an arrest had occurred, the report was a highly reliable piece of evidence; thus no due process violation was found.
Problems posed by the necessity of securing direct testimony from distant areas may be alleviated by the holding of the preliminary inquiry as closely as possible in time and place to the alleged violation. Morrissey, 408 U.S. at 485. When the probationer’s right to cross-examine those providing adverse information is scrupulously observed at this inquiry and an appropriate record is made, we perceive little difficulty in using that record at the formal revocation hearing, when securing the live testimony of witnesses to the violation would be burdensome. In any case, the practicality of obtaining this most reliable primary evidence is one of the factors to be taken into account by the district court when it strikes the due process balance on the propriety of admitting offered evidence of a secondary character.