Showing Bogey's Ace in the Hole by Marja McGraw

The only people who might strike terror in the hearts of Chris and Pamela Cross are the Church Ladies who want them to find a missing friend. When the friend turns up on her own, Chris finds a new kind of terror—a Murder for Hire plot the woman has overheard. Chris is a dead ringer for Humphrey Bogart and somehow that brings out the trust in people with problems.

Ride along in Chris's vintage Chevy with the Church Ladies, his wife Pamela, their son Mikey, and two overzealous yellow Labrador retrievers while they try to find not only a potential killer, but the intended victim.