Jack Olson is also from Seattle and like Ann Rule
I like his story telling
In June of 1982, wealthy Houston attorney, James Campbell, and his wife Virginia were shot to death in their bed while their grandsons, ages seven and eight, camped out in sleeping bags at the foot of the Campbells' bed. The frustrated police shelve the case after about 30 months of investigation, claiming the case has gone cold. The murder victims' daughter and her husband hire a private investigator to continue the investigation.
Kim Paris, a young, free-spirited private investigator on her first major case, opens up a whole new area of investigation into the formerly cold case - turning up the heat on the prime suspect, Cindy Campbell Ray, James and Virginia's younger daughter. Close to two years after the murders, Kim locates and befriends David West, an ex-Marine and Cindy Campbell Ray's lover. He confesses to shooting Cindy's parents at her behest, mistakenly believing that James Campbell had been sexually molesting Cindy throughout her childhood, and that Virginia Campbell was physically abusing Cindy as well.
Cold Kill: The True Story of a Murderous Love by Jack Olsen is a somewhat unusual true-crime study, not because the case is ultimately solved by a private detective rather than the police, and not because the final disposition of the case is not included, but, rather, because of its searching psychological depiction of the killers. I also have Daddy's Girl: The Campbell Murder Case by Clifford Irving, which is another book about this case which covers the murder trial. However, I give Cold Kill: The True Story of a Murderous Love by Jack Olsen an A+!