Michael Chadd Boysen is charged with aggravated murder in the deaths of Robert R. Taylor, 82, and Norma J. Taylor, 80. They were strangled in their Renton home on March 8, a day after Boysen was released from prison.
The grandparents had hosted a family welcome home party for Boysen the night before, after his release from prison in Monroe, charging documents said.
After the killings, Boysen stole cash and credit cards from the deceased couple, then took their car and went on a shopping spree, spending around $1,400 at Fred Meyer and Walmart to buy an iPad, a laptop, music CDs, and a pre-paid cellphone, detectives say.
He was arrested three days later in a standoff at a Lincoln City, Ore., motel where the manager recognized him from news reports.
At a hearing Monday in King County Superior Court his trial was set for early next year.