OLYMPIA, Wash. -- A husband and wife have died in a home near Olympia in what police said is a case of carbon monoxide poisoning, KIRO 7 Eyewitness News reported.

The couple's daughter-in-law found the couple dead in their home when she was dropping off her daughter there Wednesday morning.

The couple were the grandparents of the child and were to have baby-sat the girl.

The girl's mother noticed the couple's car idling in the closed garage.

The couple apparently were warming up the car and went into the house, forgetting about it while the deadly gas seeped in.

They were aged 67 and 64.

Their dog was found dead as well.

Police said it appeared to be accidental.