A Cold Case Murder - Jim Richards Murder Mysteries, #43

Jim Richards is back on the job. Jim and Penny help a young girl to buy her baby's food at a grocery when the girl was short of cash. They drove her home and met her daughter, a 4-year-old bundle of energy. The girl lives in a substandard housing project and Jim, with prodding from Penny, offers her a job at the firm. The girl reveals that her husband was murdered two years ago and the killer was never found.
Jim teams up with LVPD Detective Greg Warren and they go to track the killer with very little to go on. This book is a novella, longer than a short story, but shorter than a novel. It's the 43rd book in the Jim Richards series.