Updated

A Washington state man who killed his grandparents with a shoelace after they threw him a party to welcome him home for prison has entered a modified guilty plea to charges of aggravated first-degree murder.

Michael Chadd Boysen faces life in prison without the possibility of release when he's sentenced Oct. 18. He admitted Friday in King County Superior Court that a jury likely would convict him in the March 9 strangulation deaths of 82-year-old Robert R. Taylor and 80-year-old Norma J. Taylor at their Renton home.

Boysen was arrested three days later after a standoff at a Lincoln City, Ore., motel. He had taken cash and credit cards from the home.

Boysen had been released from prison the day before the killings after serving time for attempted burglary. His grandparents picked him up at the Monroe Correctional Complex and held a party for him that night.

Prosecutors declined to seek the death penalty after consulting with the victims' family.