"What could be the motive in this one - that's the puzzling thing to me," says Patty Laronde, a friend of the couple, "Just truly kind people."
Family members identified the couple as Robert R. and Norma J. Taylor. They were both in their early 80s.
Detectives say they are looking for the couple's 26-year-old grandson, Michael Boysen, in connection with the murders. They say he was at the home in the 16200 block of 145th Avenue SE on Friday night but hasn't been seen since. Investigators also fear Boysen has been searching for additional weapons, calling him an "extreme danger to the public and police."
Detectives are also trying to locate the couple's car that they believe Boysen may now be driving. It's described as a red 2001 Chrysler 300 with Washington license plate number 046-XXU. It might also have a memorial ribbon magnet on the trunk.
Boysen was released from prison on Friday after serving a sentence for a residential burglary conviction. His criminal history includes felony convictions for robbery. Boysen is 5-feet-10-inches tall and weighs about 170 pounds.
Ronna Smith, who lives nearby, says she didn't see or hear anything until her neighbors' home became a crime scene.
"Detectives came to our door at midnight asking us if we'd seen or heard anything," she says. "It's not something we would have ever expected to happen in this neighborhood, so it was a little scary."
The Taylors were members of the local Church of Jesus Christ of Latter-day Saints.
"He was a very, very high level respected man - kindest, softest, gentlest man," says Smith.