S4·E9 Quid Pro Quo

Rachel and the VCTF team search for a serial killer (guest star Greg Kean) who strangles women with knots of their own hair, but when the latest victim proves to be the daughter of powerful mob boss James Perrone (guest star Ray Wise), the FBI profiler must gain the grieving father's confidence to learn more about her habits. Meanwhile, Rachel is under pressure from the Bureau's Organized Crime Division to take advantage of her access to Perrone and wear a wire to trick him into confessing to a fellow mobster's murder, thereby ending a lengthy investigation.