H is for Homicide (1991) written by Sue Grafton

The eighth novel in the Kinsey Millhone series opens in the midst of troubling times for California Fidelity, the insurance company Kinsey does occasional freelance work for in return for office space. First, a recent employee and friend of Kinsey's, Parnell Perkins, is shot and killed - and the police investigation seems curiously lacking in results. Second, in the wake of poor profit figures, company troubleshooter Gordon Titus (or 'tight-ass' as he is immediately nicknamed) arrives to shake things up. The informal arrangement with Kinsey seems high on his list of targets.