Deadly Rendezvous by Diane Davidson

Lieutenant Toni Underwood is the classic soft-hearted cop with the hard-boiled attitude, and she is baffled by her newest case - a string of brutal murders, in the middle of the desert, bodies dumped on the Interstate. As Toni and her partner Sally search for clues, they unravel a sinister network of drugs, local corruption, and murder.

Set in picturesque Palm Springs, California, this chilling, fast-paced mystery takes many unexpected twists and turns, finally revealing the dark side of the human mind, as well as the enduring love between two women.