Murder in Miniature by Margaret Grace.
Now that Gerry Porter is a widow, one of the ways she fills her time is as the chair of the local dollhouse committee. Linda, one of the members of the committee, is a talented miniaturist, but a very difficult individual. She disappears in the middle of the annual miniatures fair, then calls Gerry in the middle of the night to come and get her from a remote location near a freeway off-ramp. Since Gerry has her 10-year-old granddaughter, Maddie, with her, she's more than a little annoyed, but becomes even more so when a dead body is found at that location the next day.
Gerry and Maddie are curious, tenacious and pretty darned smart, to the frustration of Gerry's police officer nephew Skip, who is worried that his aunt and his niece will get in serious trouble.
Margaret Grace is the pseudonym of Camille Minichino, the author of the Periodic Table Mysteries. Not being at all scientific, I haven't read any of them, but I'm fairly certain that the Miniature Mystery series is quite different.
I really enjoyed this one. Gerry is a cool grandmother, and I look forward to reading more about her.