A prosecutor says an inmate killed his cellmate at a Pennsylvania prison because he wanted his own private cell.

Forty-five-year-old Lawrence Peterson Jr., formerly of Easton, will now serve a life sentence on top of the 40- to 80-year term he had been serving for a violent robbery.

Clearfield County District Attorney Bill Shaw planned to pursue the death penalty but decided to skip the trial after Peterson said Friday he was willing to plead guilty to first-degree murder and take a life sentence for the Aug. 2, 2013, beating of 59-year-old William Keitel.

Keitel died in the infirmary at the state prison in Houtzdale nine days later.

Shaw says it would have been a "terrible waste of tax dollars" to push for a trial.