What type of inmate is not eligible for release on parole due to the nature of their sentence?

An inmate serving a life sentence without parole is not eligible for release on parole because their sentence is specifically designed to restrict any possibility of early release. This type of sentence implies that the individual is required to serve their entire life in prison without the chance of parole, reflecting the severity of their crime and the intention of the justice system to ensure that they do not re-enter society. In contrast, sentences for theft, misdemeanor offenses, and drug possession may allow for the possibility of parole under certain conditions, making them eligible for potential early release.