DON AND THE FBI TEAM MUST INVESTIGATE THE DEATH OF A FELLOW AGENT WHO WAS WORKING UNDERCOVER AS AN L.A. GANG MEMBER, ON "NUMB3RS," FRIDAY, JAN. 6

Will Patton ("The Agency") Guest Stars

"The O.G." -- When a fellow FBI agent working undercover is killed in a gang retaliation, Don and his team must investigate, on NUMB3RS, Friday, Jan. 6 (10:00-11:00 PM, ET/PT) on the CBS Television Network. Rob Holcomb directed the episode written by Andrew Dettmann.

Will Patton ("The Agency") guest stars as LAPD Lieutenant Gary Walker, who is in charge of LAPD's Gang Impact Team.

When Don and his team are called to the murder scene of a Los Angeles gang member, they learn that it is a fellow agent who had been working undercover. Without exposing the agent's cover, Don must investigate his murder by a rival gang and try to crack the gangs' leadership and territories to find the suspect. But the agents are surprised when they learn who is responsible for the source of the rivalry.

Don Eppes: Rob Morrow
Charlie Eppes: David Krumholtz
Alan Eppes: Judd Hirsch
David Sinclair: Alimi Ballard
Larry Fleinhardt: Peter MacNicol
Megan Reeves: Diane Farr
Colby Granger: Dylan Bruno
Det. Gary Walker: Will Patton
Olivia Rawlings: Tamara Taylor
AUSA Robin Brooks: Michelle Nolden
John Owens: Allan Louis
Travis Grant: Aldis Hodge
Karen Rhimes: Chastity Dodson
Anthony: Elijah Kelley

RATING: To Be Announced