This is book 7 of the "Mac McRyan" series.

This note contains spoilers for the book.

Another serial killer. Handled with "help" from the BAU.

However, the BAU consultant is actually the person running the killer from behind the scenes.

Truthfully, I was worried about that much earlier, and was a bit disappointed to discover that was actually the answer. It did maintain the level of plot twists I've come to expect, though.