Greed and a Mistress — Marti Talbott

When a child of the rich and famous went missing, and years of searching turned up nothing, a dying sister's last hope lay with the Jackie Harlan Detective Agency. However, what the detective team uncovered led them to Portland, Oregon, where the object of their search was involved in a murder trial. All they could do was wait, so they patiently watched a trial that became more and more fascinating. There was little doubt as to the defendant's guilt, but there were lots of unanswered questions, including, which of Mrs. Lockhart's four children hired him to kill their mother.