On the night of August 22, 1979, John Dorcheus, a bouncer at the Bouquet Bar in Boise, was approached by one of the waitresses. She complained that a friend of his, defendant Michael Kaiser, was bothering her. Kaiser, who had been drinking heavily that afternoon and evening, took offense to Dorcheus’ request that he leave the bar. While being escorted out, Kaiser suddenly struck Dorcheus in the head, knocking him to the floor unconscious. Another bouncer stepped up to hustle Kaiser from the premises. The police arrived during the ensuing struggle.
In the meantime, Dorcheus had recovered from the blow and effected a citizen’s arrest of Kaiser charging him with battery. After receiving medical treatment for minor injuries, Kaiser was taken to the county jail and booked. A few minutes later he posted bond and was released. After the bar closed, Dorcheus went home with some of his co-workers to “let off steam,” as was their custom. It was not long, however, before Dorcheus was alone with his roommate. As they talked in the early morning hours, Kaiser came in through the open front door. Words were exchanged and *502Dorcheus leapt to his feet and began to grapple with Kaiser, who was then holding a loaded .32 caliber semi-automatic pistol. A shot was fired; then two more. At this point the roommate hurriedly left the scene. He later testified that he heard two more shots as he rushed out.
When the police arrived, they found Dorcheus dead, shot four times. The next day, Kaiser, who had driven to California immediately after the shooting, turned himself in. He was charged with first degree murder, I.C. § 18-4003, and with using a firearm during the commission of that murder, I.C. § 19-2520. Following a jury trial he was convicted of second degree murder and sentenced to an indeterminate life term. I.C. § 18-4004. The jury also found that Kaiser did in fact use a firearm in the commission of the murder and the district court therefore gave him an additional fifteen-year indeterminate sentence, to run consecutively to the first sentence. I.C. § 19-2520. Kaiser appeals, contending that the district court abused its discretion in pronouncing these sentences.
In view of Kaiser’s contention that his sentences were excessive and were an abuse of discretion, we must consider whether an indeterminate sentence for a term “not to exceed life imprisonment” can be enhanced by an additional consecutive term under I.C. § 19-2520. To our knowledge this question has not previously been decided in Idaho.
The statute provides in part:
Any person convicted of [one of the enumerated offenses] who carried, displayed, used, threatened, or attempted to use a firearm while committing the crime, shall, in addition to the sentence imposed for the commission of the crime, be imprisoned in the state prison for not less than three (3) nor more than fifteen (15) years. Such additional sentence shall run consecutively to any other sentence imposed for the above cited crimes.
In construing § 19-2520 our Supreme Court has held that the carrying of a firearm during the commission of a felony is not a separate crime nor does it fix a mandatory sentence for such an act. “Rather, in scope and application, I.C. § 19-2520 can be analogized to the habitual offender statute.” State v. Cardona, 102 Idaho 668, 670, 637 P.2d 1164, 1166 (1981) (footnote omitted); see also State v. Smith, 103 Idaho 135, 645 P.2d 369 (1982). “The legislature has clearly said that any person convicted of certain crimes while carrying, displaying, using, threatening, or attempting to use firearms while committing the crime shall have their sentence for the crime enhanced.” State v. Thompson, 101 Idaho 430, 439, 614 P.2d 970, 979 (1980) (Shepard, J., concurring and dissenting). To “enhance” simply means to make greater; it is synonymous with “increase.” BLACK’S LAW DICTIONARY 475 (5th ed. 1979). Thus, the total punishment, by imprisonment, for an enumerated crime committed with a firearm may exceed, by as much as fifteen years, the maximum punishment for the same crime committed without the use of a firearm.
In spite of the mandatory language of § 19-2520, it is obvious that an enhanced sentence need not be given in every case covered by the statute. Taken literally, § 19-2520 would require a district judge to impose an additional term of not less than three years even where the underlying sentence might be the death penalty. This would be a meaningless application of the statute. It likewise would be a useless act to enhance a fixed life sentence where there is no possibility of parole.
We also find it conceptually difficult to apply the enhancement provisions to a sentence calling for an indeterminate life imprisonment. A sentence to the custody of the Board of Corrections for a term not to exceed life terminates only upon the death of the inmate or by a pardon granted by the Commission of Pardons and Parole. A sentence is not terminated by parole. When an inmate is released on parole his sentence continues until it terminates by operation of law or until the Commission of Pardons and Parole grants a final discharge to a person on parole prior to the expiration of the sentence. I.C. § 20-233. *503The Commission of Pardons and Parole also has authority to change a sentence through its power of commutation, to one that is less severe. Commutation, however, results in a sentence different than the one imposed by the court.
We recognize that the district judge here thought that by adding the fifteen-year “enhancement” sentence he would be increasing, from ten years to fifteen years, the minimum time that Kaiser would have to serve before parole. He concluded that under the life sentence Kaiser would serve a minimum of ten years, as mandated by I.C. § 20-223. He assumed that, in addition, Kaiser would be required to serve one-third of the fifteen-year enhancement sentence. It could be argued that the legislature intended that § 19-2520 would increase the minimum time a prisoner would have to serve before parole eligibility. It will have that effect in some cases. However, such an intent is not expressed in the statute.
We are unable to construe the statutes in the manner envisioned by the district court. To do so would produce capricious results in some cases. For example, a prisoner who received an indeterminate term of forty years imprisonment for second degree murder would be eligible for parole in ten years. I.C. § 20-223. Another prisoner who received a thirty-year indeterminate term for the same crime, enhanced by an additional ten years, would have to serve thirteen and one-third years before becoming eligible for parole, following the theory of the court below.
In fact, there is nothing in § 19-2520 that would require one-third of the enhancement sentence (if treated as a separate sentence) to be served before parole eligibility. The same can be said about I.C. § 20-223, our general parole eligibility statute. On the other hand, companion statutes to § 19-2520, sections 19-2520A, -2520B and -2520C, all contain restrictions against early release on parole where these enhancement provisions are applicable. The companion statutes carry a different import.
Because it is not clear that § 19-2520 requires the result intended by the district judge, we must not supply — by judicial construction — what is lacking. “It is a well-settled principal [sic] of law that criminal statutes must be strictly construed. [Citations omitted.] This principle extends not only to the elements of the substantive crime, but also to the sanctions potentially involved.” State v. Thompson, 101 Idaho 430, 437, 614 P.2d 970, 977 (1980). “Ambiguity concerning the ambit of criminal statutes should be resolved in favor of lenity.” Id. We believe that the Commission of Pardons and Parole should treat a sentence imposed under I.C. § 19-2520 as a segment of one total sentence for the purposes of determining parole eligibility under I.C. § 20-223. The commission should apply the provisions of § 20-223 against the total sentence to determine whether eligibility for parole has been obtained in any given case.
We think I.C. § 19-2520 must be construed so that the underlying sentence and the enhancement sentence can be viewed as one continuous sentence with two distinct segments. Under this view, if the underlying sentence was life imprisonment, pragmatically there can be no additional enhancement sentence to run consecutive to the “sentence imposed.” A life sentence does not allow for any further “enhancement.” Accord People v. Walker, 18 Cal.3d 232, 133 Cal.Rptr. 520, 555 P.2d 306 (1976); see also People v. Meredith, 29 Cal.3d 682, 175 Cal.Rptr. 612, 631 P.2d 46 (1981). We conclude that the fifteen-year enhancement sentence in the present case must be vacated.
It is important to remember that we are not talking here about separate punishments for multiple offenses. We are dealing only with one crime, murder in the second degree, and the permissible limits of punishment for that one crime. However, where two or more crimes are committed by the same defendant, then it is entirely possible for the defendant to receive a life sentence for one of the crimes and a consecutive term (or terms) of imprisonment *504for the other crime(s). Moreover, it is proper to charge a defendant with the use of a firearm and instruct the jury accordingly, even if the underlying felony is one for which a sentence to life imprisonment may be imposed. This is so because the jury may find the defendant guilty of a lesser included offense, or an appellate court might reduce the degree of the crime to one for which a life term is not prescribed. Thus the finding that a firearm was used would be relevant. See People v. Walker, supra. When a sentence is enhanced under I.C. § 19-2520 each segment should, of course, be separately pronounced and set forth in the judgment of conviction and commitment so that the propriety of either component of the sentence can be determined in the event of any judicial review of the sentence.
We now address Kaiser's assertion that the indeterminate life sentence was excessive. If a sentence is within the statutory maximum, it will not be disturbed on appeal unless the appellant affirmatively shows a clear abuse of discretion. State v. Cotton, 100 Idaho 573, 602 P.2d 71 (1979). The length of the sentence imposed here was the maximum allowed by law.1 Thus Kaiser must show a clear abuse of discretion on the part of the district court before the sentences will be overturned. A clear abuse of discretion is shown if a sentence is unreasonable considering the particular facts of the case before the court. State v. Toohill, 103 Idaho 565, 568, 650 P.2d 707, 710 (Ct.App.1982). A sentence is reasonable only to the extent that the term of confinement does not exceed the minimum sentence necessary to accomplish “the primary objective of protecting society and to achieve any or all of the related goals of deterrence, rehabilitation or retribution applicable to a given case.” Id.
As we have previously noted, an inmate serving an indeterminate life sentence for second degree murder becomes eligible for parole consideration after ten years. I.C. § 20-223. Therefore, pursuant to this statute and consistent with our treatment of such sentence in State v. Wilde, 104 Idaho 461, 660 P.2d 73 (Ct.App.1983), we will assume — solely for the purpose of establishing a term of confinement for appellate review — that the term of confinement will be at least ten years. We must therefore decide whether, under the facts viewed reasonably, a term of confinement for ten years “would exceed the period of confinement which appears necessary” to accomplish the sentencing objectives. State v. Toohill, 103 Idaho at 569, 650 P.2d at 711. It is incumbent upon the appellant to demonstrate that the sentence meted out exceeded what was necessary. We further note that “[i]n deference to the discretionary authority vested in Idaho’s trial courts, we will not substitute our view for that of a sentencing judge where reasonable minds might differ.” Id. at 568, 650 P.2d at 710.
At the sentencing hearing, the district court made several observations regarding Kaiser. First, Kaiser was a multiple offender. Although some of his convictions stemmed from felony charges, all of them appeared to be misdemeanors, e.g., credit card fraud, petit theft, petit larceny and check forgery. Second, the psychological reports prepared during the presentence investigation indicated that Kaiser was a borderline sociopath, which the district court defined as one “with a low or no conscience structure.” Third, Kaiser also had a history of alcohol and drug abuse. Fourth, the district court also stated that Kaiser had killed a “witness,” since the victim had filed charges against Kaiser for battery and presumably would have been the key witness in any trial arising out of that charge. The court noted that this is one factor which might call for the death penalty in a first degree murder case. Finally, the district court emphasized the seriousness of the crime — “the only one more *505serious than this is first degree murder.” The court explicitly considered the deterrent effects of a severe sentence. On the other hand, the court was also concerned with the possibility of rehabilitation. The court rejected a fixed life sentence — the maximum penalty for second degree murder — because of the hope harbored for Kaiser’s eventual rehabilitation and reentry into society.
After carefully examining the record, including the presentence report, we cannot say that the indeterminate life sentence imposed here was unreasonable. The district judge conscientiously weighed his alternatives, keeping in mind the sentencing objectives and the particular facts of the case before him. We believe that under a reasonable view of the facts considered by the district judge, the term of confinement presumed to result from this sentence did not exceed the period necessary to accomplish the goals of protection of society, deterrence and rehabilitation. Therefore, while we vacate the fifteen-year enhancement sentence for use of a firearm, we affirm the indeterminate life sentence.
WALTERS, C.J., concurs.. As an alternative sentence, the judge could have sentenced Kaiser to a fixed term of life imprisonment under I.C. § 19-2513A, without possibility of parole. He consciously rejected that option in favor of an indeterminate sentence which would allow for rehabilitation and eventual release back into society.