Die With Me by Elena Forbes

When a teenage girl falls to her death at a church, it first seems like suicide. But then a witness comes forward to say that she saw the girl with a man right before her death. When the toxicology results show that she had drugs in her system, a murder inquiry is launched with DI Mark Tartaglia leading the investigation, along with his female subordinate, DS Sam Donovan. Soon the team finds that someone named “Tom” has been killing depressed young women around London. With few clues to go on, Tartaglia needs to take his investigation “outside the box.” Die With Me is the start of a new mystery series and is similar to the Duncan Kincaid and Gemma James books by Deborah Crombie.