The Wedding Guest by Jonathan Kellerman, 368 pages

In the middle of a "Saints and Sinners" themed wedding, a bridesmaid finds a young woman's dead body in the restroom. None of the wedding guests claim to know the well-dressed victim--but Delaware and Sturgis aren't so convinced.

At this point, I don't love these books, because the killer is never anyone you met until the very, very end so the reader doesn't have a chance of figuring it out. But I've been reading them since about the 4th one came out (this is number 34) and Alex and Milo are almost family at this point, and you stick with family no matter what, lol.