Mr. Wildermuth is a prisoner in the Colorado state system convicted of first degree murder, serving a life sentence which began in 1975. He has appeared before the Parole Board several times. The Board has denied parole each time. Mr. Wildermuth commenced this 28 U.S.C. § 2254 action after his last parole hearing in 1995.1 He appeals from an order of the district court denying his petition.2 We affirm.
In his petition, Mr. Wildermuth alleges that the Parole Board violated his constitutional rights by requiring that he complete a sex offender treatment program (“SOTP”) before becoming eligible for parole. Mr. Wildermuth asserts that he need not complete the SOTP because his crime was not sexual in nature.
*1236The magistrate judge held an evidentiary hearing at which a Parole Board member, Ms. Scott, testified.' The magistrate judge found her testimony credible and therefore recommended that the district court find no constitutional violation had occurred. After reviewing the entire record and considering Mr. Wildermuth’s objections to the magistrate’s findings, the district court adopted the recommendation and denied relief.
On appeal, Mr. Wildermuth argues that the district court erred in finding that the Board had not violated his constitutional rights. He also contends that the district court should-have held an evidentiary hearing because- Ms. Scott’s testimony before the magistrate was inconsistent with her statements recorded at the parole hearing.
When reviewing a district court’s denial of a habeas petition, we accept the court’s findings of fact unless, they are clearly erroneous. See Brewer v. Reynolds, 51 F.3d 1519, 1522 (10th Cir.1995), cert. denied, 516 U.S. 1123, 116 S.Ct. 936, 133 L.Ed.2d 862 (1996). We review the court’s conclusions of law de novo. See id.
Before the magistrate, Ms. Scott testified that Mr. Wildermuth was denied parole for several reasons. She noted that he has never expressed remorse for his conduct and has changed his account of the crime multiple times. Her major concern, she testified, arose from Mr. Wildermuth’s statement that when he gets drunk, he blacks out and becomes violent: “[Tjhere’s no indication at all that this cannot reoccur. Because when he gets drunk he gets violent and he blacks out. And he commits these types-of crimes. And that’s a scary thought to me, and to me that makes him a public risk.” II R.at 62-63. She conceded that Petitioner’s refusal to participate in various programs offered at the prison, as well as. the reasons for his refusal, factored into her decision.
Petitioner asserts that the district court should have held a de novo evidentiary hearing, because Ms. Scott’s testimony before the magistrate is at odds with her statements at the parole hearing. If a -party files objections to the magistrate judge’s credibility findings, the district court must undertake a de novo review of the record, which includes reading the transcript of the eviden-tiary hearing. See Gee v. Estes, 829 F.2d 1005, 1008-09 (10th Cir.1987). However, a de novo hearing is not required if the court adopts the magistrate judge’s recommendation. See United States v. Orrego-Fernandez, 78 F.3d 1497, 1501 (10th Cir.1996); see also United States v. Raddatz, 447 U.S. 667, 681 n. 7, 100 S.Ct. 2406, 65 L.Ed.2d 424 (1980) (district court’s rejection of a magistrate judge’s proposed findings on credibility without seeing and hearing the witness whose credibility was at issue could give rise to serious questions). Because the district court accepted the magistrate judge’s findings and credibility determination, a de novo hearing was not required..
Mr. Wildermuth is not entitled to mandatory parole. See Thiret v. Kautzky, 792 P.2d 801, 805 (Colo.1990) (only inmates serving sentences for crimes committed between July 1, 1979 and July 1, 1985, are entitled to mandatory parole). Thus, the district court reviews the Parole Board’s action for abuse of discretion, asking whether the Board’s action resulted “in an abridgement of the petitioner’s constitutional rights.” Paz v. Warden, Fed. Correctional Inst., 787 F.2d 469, 473 (10th Cir.1986) (Billiteri v. United States Bd. of Parole, 541 F.2d 938, 944 (2d Cir.1976)); see also Schuemann v. Colorado State Bd. of Adult Parole, 624 F.2d 172, 173 (10th Cir.1980). We review the district court’s decision de novo. See Paz, 787 F.2d at 472-73.
“[W]here the denial of parole ... rests on one constitutionally valid ground, the Board’s consideration of an allegedly invalid ground would not violate- a constitutional right.” Bloodgood v. Garraghty, 783 F.2d 470, 475 (4th Cir.1986). Here the Board’s denial rested upon several valid reasons: Mr. Wildermuth’s lack of remorse, his inconsistent stories, and his violent tendencies when drunk. We need not reach the propriety of the Board’s consideration of the SOTP issue, because even if the Board considered Mr. Wildermuth’s refusal to participate in the SOTP in reaching its decision, no error occurred. See id.; Solomon v. Elsea, 676 F.2d 282, 290-91 (7th Cir.1982) (so long as- sufficient evidence was before Parole Board to support its decision, its actions are not an *1237abuse of discretion). We see no reason to disturb the Board’s decision or that of the district court.
The judgment is AFFIRMED.
. Mr. Wildermuth may file a petition for writ of habeas corpus in federal district court without first seeking review of the Board's action at the state level. See Mahn v. Gunter, 978 F.2d 599, 600 n. 3 (10th Cir.1992) (citing Schuemann v. Colorado State Bd. of Adult Parole, 624 F.2d 172, 173 (10th Cir.1980)).
. Mr. Wildermuth filed his petition prior to the passage of the Antiterrorism and Effective Death Penalty Act. Because the district court granted a certificate of probable cause, we may review this appeal. See United States v. Kunzman, 125 F.3d 1363, 1364 n. 2 (10th Cir.1997).