It was the couple's daughter-in-law Darlet who made the horrific discovery. She came to her in-laws house like she does every day to drop off her 2-year-old son Sorin.

Nona and Dan Holm babysit Sorin while dad works and mom works on her nursing degree.

When the Holms didn't answer the door, Darlet and a neighbor forced their way inside.

"We believe with the van running it filled the house with carbon monoxide," Olympia Fire Chief Robert Lord said.

Sorin's other grandma came running when she heard the news. Her reaction was like everyone else's.

"They were the most awesome people you'd ever meet in your life," Cheryl Kent said.

Emergency crews found Nona and Dan Holm in their bedroom, still in their nightclothes. Thurston County Sheriff Chief Deputy Dan Kimball thinks they were overcome by carbon monoxide.

"The theory here is this is a tragic accident -- the vehicle was accidentally left running," Kimball said. He says an autopsy will help determine just how long the couple's van had been idling. "We think it could have been running since last evening," said Kimball.

"When we first got here," Lord said, "we checked the (carbon monoxide) levels and they were two or three times higher than would normally be considered safe."

Carbon monoxide is a silent killer. The odorless and colorless poisonous gas attacks before you even know what's happening.

Ron Olson and Dan were best friends. They made arrangements Tuesday night to get tickets to see Nona on stage -- she was an actress and singer thrilled to take center stage in a local production this Saturday night.

"It's a sad, sad thing to happen to such wonderful people," said friend Jolene Olson. "I guess you never know, huh?"

Fire officials once again warn not to warm up your car in your garage. Also, they strongly advise people think about buying a CO detector. Battery operated detectors sell for as little as $25.