Opponents of the death penalty regularly claim that a life sentence prevents a killer from killing again just as effectively as an executed death sentence.  But it doesn't.

Bill Lindelof reports for the Sacramento Bee:

The death of an inmate at New Folsom prison is being investigated as a homicide.

The 51-year-old inmate was found unresponsive in his cell a little after 9 p.m. Wednesday during a prisoner count. His name has not been released.

The inmate has been in prison since Dec. 10, 2001, serving a 25-year-to-life sentence from Contra Costa County for assault with intent to commit a sex act. Cause of death was not released.

His 46-year-old cellmate has been identified as a suspect in his death and is being housed in a segregation unit pending the investigation, according to a prison press release. The suspected killer has been in state prison since Nov. 9, 1986, serving a 17-year-to-life sentence from Alameda County for second-degree murder.

In this case, the prior could not have been a death sentence, as that sentence is not available for second-degree murder.  That is why we divided murder into degrees in the first place.  The case illustrates, though, that life-sentenced murderers can and do kill again.