Tonight I Said Goodbye — Michael Koryta

Investigator Wayne Weston is found dead of an apparent suicide in his upscale Cleveland suburban home. His wife and six-year-old daughter are now missing. The police think the former Marine murdered them. Hoping to exonerate his son, Weston's father hires PIs Lincoln Perry and Joe Pritchard.

Perry and Pritchard soon discover there is much more lying beneath the surface, including rumors of gambling debts, extortion, and a Russian mob that likes to wield baseball bats. But just when Perry and Pritchard believe they are making swift progress, a millionaire real estate tycoon and the FBI advise them to back off of the investigation.
Then without warning, another murder suddenly forces them to change direction in the case as they uncover a trail of deadly twists--but the most shocking secret of all has yet to be unraveled...