Michael Boysen of Renton pleaded not guilty Thursday morning to two counts of aggravated first-degree member in the strangulation deaths of his grandparents in Fairwood March 9.

The 26-year-old Boysen was arraigned on the charges at the King County Courthouse. He is being held without bail at the King County Jail in Seattle.

A case-setting hearing is scheduled for April 18 at the King County Courthouse. King County Superior Court Judge Douglass North will hear the case.

Boysen’s mother, Melanie Taylor, found her parents, Norma and Robert Taylor, dead in their home at about 6 p.m. March 9 after another relative was unable to contact them at home.

Boysen was arrested in Lincoln City, Ore., March 12 after 10-hour standoff with police.

If he’s convicted, Boysen would face either life in prison or the death penalty.