Sin in Their Blood

Originally published in 1952.
An open and shut case of murder! Matt Ranzino had sworn off sleuthing; he'd had a bellyful of violence. But when a beautiful blonde was murdered and Matt was asked to solve the crime, he took the job. When the blonde's husband committed suicide, the cops named him the killer and closed the case. But Matt smelled a put-up job. He knew the real killer -- but why risk his life to prove it? Then he met Mady, the only dame he ever really wanted.