JACKSONVILLE, Fla. -

A 58-year-old Jacksonville man pleaded guilty Thursday to second-degree murder for the stabbing death of his girlfriend.

In April 2012, Thomas Webster and Patricia Berner were arguing at their home when he stabbed her in the back with a large kitchen knife.

Webster then drove to a local convenience store and asked the clerk to call 911. When officers arrived at the store, Webster told police that he may have killed the victim.

Police found Berner dead in the couple's home.

Webster faces life in prison. He will be sentenced the week of Oct. 28.