Brian Groh

The BAU works to capture a serial killer who has evaded capture by altering his appearance.

During the week of Halloween, a murderous psychopath taunts the team by using the Internet to leave clues to the next victim's identity.

Avery welcomes D.B. Russell to the team as they investigate a burglary/homicide committed by someone who hacked the home's security system remotely. Also, Avery considers moving to a new position within the hierarchy of the FBI, Krumitz is a witness in his sister's trial, Elijah deals with a delicate family situation and more is revealed about Nelson's and Raven's backgrounds. Ted Danson joins the cast as D.B. Russell, the new Director of Next Generation Forensics, who transfers to Washington, D.C. from Las Vegas.

Will returns to an unfamiliar workplace. At home, Katie tries to stay on her best behavior. Broussard and his cell make a startling discovery about the Wall.

Martin attempts to find Teller’s mysterious workshop and winds up aiding another professor, Logan, to win big at poker. Meanwhile, a young Italian man creates a viral video to track down the love of his life, whom he only met in passing, and a city slicker who plans to sell off his dead father’s ranch, winds up learning a lesson from a horse that makes him appreciate the rural life his father chose. Then, Martin’s sister-in-law, Abigail Kelsey, visits Clea and Jake at the board-and-care facility, much to Martin’s dismay.