THE LOST GIRLS OF ROME, by Donato Carrisi

A complex, many-layered contemporary mystery set in Rome that starts with a dying man whose chest tattoo says Kill Me, and the disappearance of a young women, only the most recent of a series. On her trail is the enigmatic Marcus, beset by nightmares from his own near-murder. No spoilers here, you'll have to read it to learn more about the plot. This is a police procedural with an off-duty cop seeking to solve a spouse's murder, and a mysterious church group of criminologists in cassocks. It's complicated by various other legal and extra-legal pursuers, until at times it becomes a bit challenging to keep it all straight. And just when you think it's all coming together, it goes off in another direction! If you like subtle puzzles with a Vatican-as-character aspect, this one will be right down your alley. It's a 4. Translated from the Italian.
Unfortunately, his web site is solely in Italian, not even a "translate" button.