The King County medical examiner's office has formally identified the elderly couple killed last weekend in their Renton, Wash., home although the cause and manner of their deaths remain under investigation.

The medical examiner said Tuesday that 82-year-old Robert Taylor and 80-year-old Norma Taylor died Saturday.

Police have surrounded a beachfront motel on the Oregon coast, where they are trying to persuade the couple's grandson, Michael Boysen, to surrender.

King County sheriff's officers have accused the 26-year-old Boysen of killing his grandparents the day after they threw a welcome home party for him after his release from prison.