By Laura L. Myers
SEATTLE (Reuters) - Police are searching for a Washington state man suspected of brutally killing his grandparents and stealing their car after they threw him a party to celebrate the convicted burglar's release from prison, authorities said on Monday.
Michael "Chadd" Boysen, 26, is wanted by Washington state authorities for the recent slaying of his grandparents, Robert and Norma Taylor, in Renton, Washington, 15 miles southeast of Seattle. The couple was in their 80s.
The grandparents had set aside a room for Boysen at their home and they picked him up from prison on Friday, helped him get a Washington state identification card and hosted a family party later that evening, police said.
Boysen's mother found the bodies of her parents on Saturday, police said. The next day, the King County Sheriff's Office issued a warrant for Boysen's arrest.
Investigators learned Boysen had previously talked about killing his grandparents, and that he also vowed to get guns and target figures of authority, police said.
Boysen had conducted Internet searches to find gun shows in the Pacific Northwest and Nevada around the time he is believed to have killed his grandparents, King County Sheriff John Urquhart told reporters.
Urquhart said Boysen did not kill his grandparents with a gun, but the sheriff declined to describe the violent manner of their deaths.
"We need to do everything we can to get this man off the street as soon as possible," Urquhart said in a statement. "His threats against authority figures make him very dangerous and unpredictable."
Police said they do not know Boysen's motive.
Boysen had served nine months at the Monroe Correctional Facility in Washington state for burglary, said King County Sheriff's spokeswoman Cindi West.
Meanwhile, authorities said they were providing protection for other Boysen family members.
(Editing by Alex Dobuzinskis and Lisa Shumaker)