UPDATE: Man Wanted in Connection with Elderly Renton Couple's Death Might Be Seeking Weapons

UPDATE: 12:15 a.m. Monday: After searching Michael Boysen's computer, King County Sheriff's investigators expressed alarm that the 26-year-old might be seeking to stockpile weapons.

Boysen, who is at-large and facing an arrest warrant in connection with the death of his grandparents, did web searches for, "GUN SHOWS all across the Pacific Northwest and Nevada," investigators said in a statement late Sunday.

"(Boysen) is considered an extreme danger to the public and police," department spokeswoman Cindi West said.

Original story:

King County Sheriff's investigators on Sunday issued an arrest warrant for Michael Boysen, grandson of the elderly Renton couple found dead in their home Saturday evening.

Boysen was last seen at his grandparent's house Friday night. Recently released from prison, the 26-year-old temporarily was staying with the couple, both in their 80s, investigators said. 

When the bodies of the couple -- he was 80 and she was 82 -- were discovered by their daughter Saturday evening around 7 p.m., both Boysen and the couple's 2001 Chrysler were missing.

"We have no idea where he is," said spokeswoman Cindi West, of the King County Sheriff's Office. "We do consider him dangerous."

Investigators have asked that anyone with information about Boysen -- described as as a white male, 5'10" and 170 pounds -- or the missing car, a red 2001 Chrysler 300, license plate 046-XXU, call 911 immediately.

"We really want people to be on the lookout for the car," West said.

The couple lived on the 16200 block of 145th Ave. S.E., in the Fairwood Greens Community of the Fairwood Golf and Country Club.

Previously, West said another relative had stopped by around noon Saturday and knocked on the front door. Getting no response, this relative called the couple's daughter. She stopped by just before 7 p.m.

She also knocked and didn't get an answer, West said. She let herself in. Then she found the couple already dead.

"The family is extremely shocked and distraught," West said.

Initially, detectives did not name Boysen as a suspect. But after serving a search warrant and interviewing the slain couple's daughter, they began to focus on the grandson.

Family members told investigators he was supposed to stay there Friday night.

Investigators did not release a cause of death, suspected motive nor any additional information about what prompted the arrest warrant.

Look here at Renton Patch for additional updates.