OPINION OF THE COURT
Petitioner Robert Stiver contests a decision by the Bureau of Prisons (the “Bureau”) denying him a one-year sentence reduction because of his previous convictions for violent offenses. Under the 1994 Violent Crime Cоntrol and Law Enforcement Act, “prisoners convicted of a nonviolent offense” are eligible for a one-year sentence reduction upon successful completion of a drug treatment prоgram. See 18 U.S.C. § 3621(e)(2)(B). 1 Stiver has been incarcerated since 1992 for possession of heroin with intent to distribute, a nonviolent offense. Because he has successfully completed a drug treatment program during this prison term, Stiver contends he is eligible for early release under the statute. Nonetheless, the Bureau denied him a sentence reduction pursuant to its regulation that categorically excludes inmates previously conviсted of a violent crime from eligibility for early release under section 3621(e)(2)(B). See 28 C.F.R. § 550.58. 2 Stiver previously was convicted of robbery and aggravated assault, both of which are violent offenses.
Stiver sought a writ of habeаs corpus pursuant to 28 U.S.C. § 2241, alleging that the Bureau’s regulation conflicts with the enabling statute, 18 U.S.C. § 3621(e)(2)(B). He further alleged that the Bureau’s regulation, 28 C.F.R. § 550.58, violates the double jeopardy and ex post facto clauses of the United States Constitutiоn. The district court denied habeas corpus relief with regard to each of Stiver’s claims, and this appeal followed.
The district court exercised jurisdiction pursuant to 28 U.S.C. § 2241. 3 Our jurisdiction arises under 28 U.S.C. § 1291. 4 We will affirm.
*577 I.
Stiver contends that 18 U.S.C. § 3621(e)(2)(B) allows the Bureau to consider only the offense for which an inmate is presently incarcerated when deciding whether to grant a sentence reduction. Thus, he argues, 28 U.S.C. § 550.58 represents an impermissible expansion of the authоrity Congress delegated to the Bureau. We review this question of statutory interpretation
de novo. See Barden v. Keohane,
When examining an agency’s construction of the statute it administers, we must first inquire “whether Congress has directly spoken to the precise question at issue.”
Chevron, U.S.A., Inc. v. Natural Resources Defense Council, Inc.,
The contested statute provides that [t]he pеriod a prisoner convicted of a nonviolent offense remains in custody after successfully completing a treatment program may be reduced by the Bureau of Prisons, but such reduction may not be more than one year from the term the prisoner must otherwise serve.
18 U.S.C. § 3621(e)(2)(B). Despite Stiver’s contention to the contrary, it is clear that section 3621(e)(2)(B) does not indicate whether “convicted of a nonviolent offense” refers to all convictions or only the most recent one, for which the inmate presently is incarcerated. Instead, its language grants the Bureau broad discretion to approve or deny a sentence reduction. In other words, section 3621(e)(2)(B) is silent on the issue of whether the Bureau may consider relevant the violent status of a prisoner’s past convictions in deciding whether the prisoner is eligible for eаrly release. When a statute expressly leaves a gap for an agency to fill with its rulemaking authority, the agency’s regulations must receive “controlling weight unless they are arbitrary, capricious, or manifestly сontrary to the statute.”
Chevron,
We find that the Bureau’s interpretation of the statute represents a reasonable accommodation of Congress’s goals of providing an incentive for inmates to obtain drug treatment while at the same time ensuring that persons likely to commit violent crimes do not receive early release. See H. Rep. No. 103-320, at 2 (1993) (describing purposes of statute). The Bureau, in the exercise of its discretion in administering the early release element of the residential drug abuse treatment program, has imposed an additional qualification: prisoners’ non-cоnviction of certain enumerated past violent offenses, in addition to the requirement that the present conviction be for a non-violent offense. It was not attempting to, and has not interpreted the phrase “convicted for a violent offense” in a manner at odds with Congress’s intended meaning, as Stiver suggests.
Stiver contends that this conclusion conflicts with our recent decision in
Roussos v. Menifee,
Our holding in
Roussos
does not control this appeal. First,
Roussos
required us to interpret a different part оf section 3621(e)(2)(B), addressing the significance of “nonviolent offense” rather than “convicted.” More importantly,
Roussos
involved only a challenge to a Bureau program statement; Stiver, on the other hand, asks us to strike down a regulation. As we noted in
Koray v. Sizer,
II.
Stiver also contends that applying the Bureau regulation to his case violates the
ex post facto
clause of the United States Constitution. This argumеnt is without merit. We have held that two conditions must be met for a law to be
ex post facto.
“First, the law must be retrospective, that is, it must apply to events occurring before its enactment. Second, the change in the law must alter the dеfinition of criminal conduct or increase the penalty by which a crime is punishable.”
United States v. Dozier,
The purpose of the prohibition against
ex post facto
laws is to assure that legislative acts “give fair warning of then-effect and permit individuals to rely on then-meaning until explicitly changed.”
Weaver,
III.
We must also reject Stiver’s argument that 28 C.F.R. § 550.58 violates the Fifth Amendment’s double jeopardy clause. The double jeopardy clause “protects against three distinct abuses: a second prosecution for the same offense after acquittal; a second prosecution for the same offense after сonviction; and multiple punishments for the same offense.”
United States v. Halper,
For the foregoing reasons, we will affirm the district court’s decision in its entirety.
Notes
. 18 U.S.C. § 3621(e)(2)(B) states
Period оf custody. — The period a prisoner convicted of a nonviolent offense remains in custody after successfully completing a treatment program may be reduced by the Bureau of Prisons, but such reduction mаy not be more than one year from the term the prisoner must otherwise serve.
. 28 C.F.R. § 550.58 provides in relevant part: Except as provided in this paragraph, an inmate ... who completes a residential drug abuse trеatment program including subsequent transitional services in a community-based program (i.e., in a Community Corrections Center or on home confinement) during his or her current commitment may be eligible, in accordance with paragraph (a) of this section, for early release by a period not to exceed 12 months. The following categories of inmates are not eligible: INS detainees, pretrial inmates, contractual boarders (for example, D.C., State, or military inmates), inmates whose current offense is determined to be a crime of violence as defined in 18 U.S.C. § 924(c)(3), inmates who have a prior conviction for homicide, forcible rape, robbery, or aggravated assault, and inmates who are not eligible for participation in a community-based program as determined by the Warden on the basis of his or her professionаl discretion.
. Under 28 U.S.C. § 2241(a), ''[w]rits of habeas corpus may be granted by the Supreme Court, any justice thereof, the district courts and any circuit judge within their respective jurisdic-tions____"
. “The courts of appeals ... have jurisdictiоn of appeals from all final decisions of the district courts of the United States....” 28 U.S.C. § 1291.
. The Bureau enumerated four such offenses: homicide, forcible rape, robbery and aggravated assault. 28 C.F.R. § 550.58. Stiver was previously convicted of robbery and aggravated assault.
