Updated

A 54-year-old inmate was sentenced to death Wednesday for killing a Washington state corrections officer in a prison chapel two years ago.

Byron Scherf is a convicted rapist who already was serving life in prison when he attacked and strangled Officer Jayme Biendl (JAY'-mee BIN'-dul) in January 2011.

A Snohomish County Superior Court jury took about an hour to convict him of aggravated murder last Thursday, and the same jury sentenced him to death. The only other possible sentence was life in prison without release.

The defense didn't dispute that Scherf strangled Biendl with an amplifier cord in the chapel at the Washington state Reformatory at Monroe. His lawyers had suggested Scherf didn't plan to kill the corrections officer, and said he blacked out in the final minutes of her life.

The jury earlier saw Scherf's video confession and heard forensic testimony about how Biendl was strangled. Scherf said he first planned to ambush and beat up Biendl over something she said to him. He refused to say what set him off.

Scherf initially cooperated with investigators and confessed but stopped because he says he was denied jail privileges that had been promised.