Killing Room by Robert Swartwood

While on vacation in Las Vegas, a businessman wakes up in a strange hotel room to find a dead woman in the bathtub. Panicked, he runs. But before he can get far, a pair of detectives stop him. Desperate, he tells them that he's innocent. That there's no way he killed the woman. That he'll do anything not to go to prison. That's when they offer him a way out. But there is no way out -- as the detectives will soon learn.