Proof of Life by J.A. Jance

Retired with lots of time on his hands, J.P. Beaumont agrees to look into the death of former adversary Maxwell Cole, who recently died in a house fire. A longtime friend of Cole's named Erin Howard had asked Beaumont to look into the circumstances around the fire, because she believes that it wasn't accidental, despite what the authorities are saying. With help from his wife, Mel, and his former contacts in the Seattle Police Department, Beaumont tries to uncover the truth for Erin. Proof of Life is the most recent book in Jance's J.P. Beaumont series and it's always so much fun to spend time with an old acquaintance.