[¶ 1] Chip A. Watkins appeals the denial of his application for a writ of habeas corpus. We affirm.
FACTS
[¶ 2] As a result of a criminal escapade in Clay County, South Dakota, in 1984, Watkins was charged with three counts of first-degree robbery (SDCL 22-30-1); one count each of first-degree burglary (SDCL 22-32-1); possession of a controlled weapon (SDCL 22-14-6); commission of a felony while armed with a short shotgun (SDCL 22-14-12); and possession of a firearm by a convicted felon (SDCL 22-14-5). Pursuant to a plea agreement, Watkins pleaded guilty to one count each of first-degree robbery and possession of a controlled weapon. On March 26, 1984, he was sentenced to ten years in the state penitentiary for the robbery conviction and two years for the possession of a controlled weapon conviction, both sentences to run concurrently. When Watkins entered the penitentiary, his good-time release date was calculated to be September 26, 1990, and his flat-time release date was set for March 26, 1994.
[¶ 3] Watkins was released on parole June 30, 1988. A warrant for his arrest was issued on September 20, 1988, and Watkins was returned to the penitentiary on September 21, 1988. The record is unclear as to how he violated his parole. The following day, the Board of Pardons and Paroles (hereinafter “the Board”) revoked Watkins’ parole and withheld one year and nine months of good-time credit as a result of the violation.
[¶ 4] Watkins was released on parole a second time on September 27, 1988.1 As a condition of this parole, he was again required to sign a standard parole agreement requiring him to keep his parole officer informed of his whereabouts at all times. In addition to obeying all municipal, county, state, and federal laws, he was also required to keep the hours specified by his parole officer and secure advance approval for use of any vehicle as conditions of his parole.
[¶ 5] After being paroled, Watkins was involved in a physical confrontation with his roommate’s friend. His roommate threatened to call the police and Watkins fled the state to avoid the possibility of parole revocation. On January 4, 1989, a warrant was issued for him as a parole absconder.2 Watkins remained at large for more than five years, living in New Mexico under various aliases. On December 9,1994, he was apprehended in Colorado and returned to South Dakota.
[¶ 6] Watkins waived his right to a preliminary hearing before the Board and a final hearing was held on January 26, 1995. At the hearing, he admitted to having failed to inform his parole agent of his whereabouts in violation of his parole agreement. Based on this admitted violation, on January 27, 1995, the Board revoked his parole and withheld seventeen months of good-time credit. The Board deemed the five years, ten months and nineteen days Watkins spent as an absconder as tolled “dead time,” inapplicable to his sentence. The effect of the reduction in Watkins’ good-time credit and the tolled “dead time” was to calculate his good-time release date as October 15,1999, and set his flat-time release date as February 15, 2000.
[¶ 7] Watkins filed a writ of habeas corpus alleging that the State was without the authority to toll his parole supervision time. *433The habeas court denied Watkins’ application. He appeals.
STANDARD OF REVIEW
[¶ 8] Habeas corpus is not a substitute for direct review. Loop v. Class, 1996 SD 107, ¶ 11, 554 N.W.2d 189, 191 (citation omitted). A habeas corpus proceeding is in the nature of a collateral attack on a final judgment; accordingly, our review is limited. Black v. Class, 1997 SD 22, ¶ 4, 560 N.W.2d 544, 546; Jenner v. Leapley, 521 N.W.2d 422, 425 (S.D.1994); Gregory v. Solem, 449 N.W.2d 827, 829 (S.D.1989).
Habeas corpus can be used only to review (1) whether the court had jurisdiction of the crime and the person of the defendant; (2) whether the sentence was authorized by law; and (3) in certain cases, whether an incarcerated defendant has been deprived of basic constitutional rights. For purposes of habeas corpus, constitutional violations in a criminal case deprive the trial court of jurisdiction.
St. Cloud v. Leapley, 521 N.W.2d 118, 121 (S.D.1994) (St. Cloud III) (internal citations omitted). The petitioner has the burden to prove by a preponderance of the evidence that he is entitled to relief. Two Eagle v. Leapley, 522 N.W.2d 765, 768 (S.D.1994); Petrilli v. Leapley, 491 N.W.2d 79, 81 (S.D.1992).
DECISION
[¶ 9] Initially, we note the habeas court concluded the Board’s authority to toll parole supervision time was granted by SDCL 24-15-24,3 and concluded “[wjhile SDCL 24-15-21 (1986) and its later versions aid in statutory clarification when a parole absconder situation arises, SDCL 24-15-24 (1983) is nonetheless effective against parole absconders in limiting good credits received while on the run.” SDCL 24-15-24 sets forth the remedies available to the Board for addressing parole violations, including parole revocation, reinstatement of the original sentence or reduction of good-time credit, in part or in whole. SDCL 24-15-21, on the other hand, provides for the tolling of parole supervision time during the period between the issuance of a warrant for a parole violation and parole revocation.
[¶ 10] The habeas court’s application of SDCL 24-15-24 as authority to reduce Watkins’ good-time credits was proper. The application of SDCL 24-15-24 to toll Watkins’ parole supervision time, however, was in error because the statute authorizes only post-violation remedies for a parole violation. SDCL 24-15-21, not SDCL 24-15-24, provides the correct framework for determining whether parole supervision time is tolled upon issuance of a warrant and applies to the “dead time” at issue in Watkins’ application for a writ of habeas.
Whether the Board’s application of SDCL 24-15-21 to toll the running of Watkins’ sentence violated the ex post facto clause.
[¶ 11] Though for the wrong reason, the habeas court’s denial of Watkins’ writ of habeas corpus reached the right result for the reasons stated below. See Kehn v. Hoeksema, 524 N.W.2d 879, 881 (S.D.1994); Sommervold v. Grevlos, 518 N.W.2d 733, 740 (S.D.1994); Cowell v. Leapley, 458 N.W.2d 514, 519 (S.D.1990).
[¶ 12] The United States Constitution expressly provides “no state shall ... pass ... any ex post facto law.” U.S.Const.Art. I, § 10. Similarly, the South Dakota Constitution provides “no ex post facto law ... shall be passed.” S.D.Const.Art. VI, § 12. The ex post facto clause is implicated only by a criminal or penal statute which “imposes a punishment for an act which was not punishable at the time it was committed or [which imposes] an additional punishment to that then prescribed.” Collins v. Youngblood, 497 *434U.S. 37, 45-46, 110 S.Ct. 2715, 2721, 111 L.Ed.2d 30, 41 (1990).
[¶ 13] Two elements are required for a finding that a statute is ex post facto: “[I]t must be retrospective, that is it must apply to events occurring before its enactment, and it must disadvantage the offender affected by it.” Weaver v. Graham 450 U.S. 24, 29, 101 S.Ct. 960, 964, 67 L.Ed.2d 17, 23 (1981) (footnotes omitted). See also Delano v. Petteys, 520 N.W.2d 606, 608 (S.D.1994); Stumes v. Delano, 508 N.W.2d 366, 371 (S.D.1993); Matter of Williams, 488 N.W.2d 667, 669-70 (S.D.1992) (Williams I).
[¶ 14] The State and Watkins do not dispute that the Board’s authority to toll parole supervision time is derived from SDCL 24-15-21, which, as amended in 1986, provides:
If the executive director of the board is satisfied that any provision of § 24-15-20 has been violated, the executive director may issue a warrant to the Department of Corrections, any law enforcement officer, or any parole agent, directing that the parolee named be arrested. Pursuant to the provisions of § 24-15-23, the parolee may be returned to the state penitentiary. Upon the issuance of the warrant, the running of the parole supervision time shall be suspended until the board has entered its final order on the revocation. The board shall credit the inmate with time spent in custody as a direct result of the parole violation.
The version of this statute in effect when Watkins was convicted did not contain the language mandating the tolling of parole supervision time upon the issuance of a parole violation warrant. The tolling language was in effect, however, when Watkins was paroled in 1988. Watkins maintains the 1986 amendment is inapplicable to his parole violation because the amendment was not in effect when he was convicted in 1984. State argues the 1986 tolling provision is applicable because it was in effect at the time of the 1989 parole violation.
[¶ 15] Watkins argues the Eighth Circuit Court of Appeals’ review of our holding in Williams I supports his argument that the application of SDCL 24-15-21 constituted an ex post facto application. Williams v. Lee, 33 F.3d 1010, 1014 (8th Cir.1994) cert. denied 514 U.S. 1032, 115 S.Ct. 1393, 131 L.Ed.2d 244 (1995) (Williams II). The Eighth Circuit concluded the revocation of Williams’ good-time credits pursuant to a statutory amendment to SDCL 24-15-24 enacted two years after his conviction was an ex post facto application of the amendment. Id. The Eighth Circuit’s decision, however, expressly declined to reach the issue of ex post facto application of SDCL 24-15-21. Id. (stating “we need not and do not reach” the issue of whether the tolling provision was ex post facto). We conclude Williams II is not determinative of the applicability of SDCL 24-15-21 to Watkins’ appeal.
[¶ 16] Watkins’ parole supervision time was suspended as a direct result of events which occurred after the 1986 amendment to SDCL 24-15-21. Watkins’ 1989 parole violation, not his 1981 convictions, triggered the tolling provisions of the statute. An amended statute is not ex post facto merely because it might operate on a fact preexisting the amendment, so long as the punitive aspects of the amendment apply only to events occurring after the amendment’s enactment. In re Ramirez, 39 Cal.3d 931, 218 Cal.Rptr. 324, 328-29, 705 P.2d 897, 901 (1985); Gasper v. Gunter, 851 P.2d 912, 918 (Colo.1993); People v. Billips, 652 P.2d 1060, 1064 (Colo.1982). While Watkins’ status as a parolee resulted from his 1984 convictions, this did not automatically make the application of the 1986 amendment ex post facto. The 1989 parole violation was a separate and distinct event unconnected to the convictions for which Watkins was originally sentenced. The amendment to SDCL 24-15-21 related only to the parole violation, not his original convictions. The tolling provision of SDCL 24-15-21 was not applied retroactively.
[¶ 17] Furthermore, Watkins was not disadvantaged by the 1986 amendment application, even assuming it was retroactive. See Weaver, 450 U.S. at 29, 101 S.Ct. at 964, 67 L.Ed.2d at 23. A critical distinction exists between the statute challenged in Williams *435II and the statute challenged by Watkins;4 SDCL 24-15-24 affects an inmate’s statutory right to a sentence reduction for good conduct and SDCL 24-15-21 affects an inmate’s discretionary privilege of parole. The statutory right to a reduction for good conduct is absolute and cannot be taken away arbitrarily. Lewis v. Class, 1997 SD 67, ¶ 20, 565 N.W.2d 61, 64; South Dakota v. Weekley, 90 S.D. 192, 240 N.W.2d 80, 83 (1976). When an inmate enters the penitentiary, he has an expectation of a reduced sentence based on good-time credits. See SDCL 24-5-1. Good-time credits actually reduce the term of an inmate’s sentence. Id. Substantial alterations to this expectation through subsequent legislative enactments violate the ex post facto clause. Lynce v. Mathis, 519 U.S. -, -, 117 S.Ct. 891, 899, 137 L.Ed.2d 63, 76-77 (1997).
[¶ 18] Parole is a discretionary conditional release and an inmate is never entitled to the privilege of parole. SDCL 24-15-1.1. While an inmate may be entitled to the calculation of a parole eligibility date, SDCL 24-15-3, he is never entitled to a grant of parole. SDCL 24-15-1.1. Parole may only be granted when it would be in the best interests of society and the inmate. Id. An inmate granted parole remains under the legal custody of the Department of Corrections until the expiration of his sentence. SDCL 24-15-1.1. Parole does not act to reduce an inmate’s sentence but rather only to change the place and conditions of the inmate’s custody.
[¶ 19] In Williams II, the Eighth Circuit concluded that because the revocation of Williams good-time credits extended the time he must serve on his rape conviction, the post-conviction amendment to SDCL 24-15-24 increased his punishment and constituted an ex post facto application. Watkins’ sentence, however, was not increased as a result of the post-conviction amendment to SDCL 24-15-21, but rather tolled until he was returned to the legal custody of the Department of Corrections to actually serve the term of his sentence. The fact that Watkins unilaterally chose to flee from law enforcement and remain a fugitive for nearly six years does not reduce the time he was required to be under the Department’s custody. During his absence, Watkins was not fulfilling the terms and conditions of his parole and, therefore, he was not serving his sentence. Tolling his parole supervision period during this period of noncompliance with the conditions of his parole delayed, but did not lengthen, Watkins’ sentence to his detriment. He has not been disadvantaged by the tolling of his parole supervision time and accordingly he has no ex post facto objection.
[¶ 20] We have reviewed Watkins’ second argument that the revocation of his parole after the expiration of his sentence violated the Fifth, Sixth, Eighth, Thirteenth and Fourteenth Amendments to the United States Constitution and find it to be without merit.
[¶ 21] Affirmed.
[¶ 22] KONENKAMP and GILBERTSON, JJ., concur. [¶ 23] SABERS and AMUNDSON, JJ., dissent.. The record does not indicate why Watkins was reparoled within a week after his arrest for his first parole violation.
. Watkins' last documented contact with his parole officer was on December 23, 1988.
. SDCL 24-15-24 provides:
If the board of pardons and paroles is satisfied that any provision of § 24-15-20 has been violated, it may revoke the parole and reinstate the terms of the original sentence and conviction or it may modify conditions of parole and restore parole status. In addition, the board is authorized to order the reduction of time in full or in part for good conduct granted under § 24-5-1. If the board does not find that the provisions of § 24-15-20 have been violated, it may restore the parolee to the original or modified terms and conditions of his parole.
. Watkins also relies on our summary reversal in High Elk v. Class, 538 N.W.2d 248, following the Eighth Circuit's ruling in Williams II, in which we stated:
[High Elk's appeal] is meritorious on the following grounds: 1. that the issues on appeal are clearly controlled by settled South Dakota law or federal law binding upon the states, Williams v. Lee, 33 F.3d 1010 (8thCir. 1994), cert. denied, [— U.S. -] 115 S.Ct. 1393, 131 L.Ed.2d 244 (U.S.1995).
High Elk, like Williams, appealed the reduction of good-time credits pursuant to an amendment to SDCL 24-15-24. The issue presented by Watkins is distinguishable from High Elk for the same reasons Williams II is distinguishable.