The Instant Enemy (1968) by Ross MacDonald
"Lew Archer is hired by Keith Sebastian, a Los Angeles business executive, to find his daughter Sandy, a high-school senior who has run off with a homeless boy. Sebastian and his wife, living on the edge of affluent bankruptcy, seem unable to communicate with their daughter. Archer finds the runaway easily enough, but before he can return Sandy to her parents, she has participated in a violent crime. Archer’s efforts to save the girl from the consequences of her actions, and to understand those actions, involve him in a savage plot twisting deep into the past. At least one old murder and some new ones confound him and the police. Archer himself is very nearly killed by an ex-cop who wants to keep the case closed, but he finally manages to open it and let some daylight in.”
I've never actually read any R MacDonald before so this was a pleasant surprise. The writing was tight and the character of Archer was different enough to keep me interested. Worthwhile.