Numb3rs Episode 6.01 Hangman

Don's team is charged with running VIP security for a big political rally featuring high profile activist Benjamin Polk. While scouting out the venue in preparation for the event, Don and his team come under heavy fire and receive a message to stay away from Polk during the rally. This overt attempt to scare Polk and the FBI away doesn't work, and Polk insists on keeping his speaking engagement at the gathering. The FBI then digs in to try and discover who is making the threat, and discover that it's a man who'd lost his son during a violent riot orchestrated by Polk to gain political street credit in order to further his own career. Furious that his son had been blatantly used as a pawn, the man, Shepard Crater, had come to LA to exact revenge. On the day of the rally Crater sets off a sequence of events to force Polk back to his hotel, where Crater is set to ambush and kill him. Charlie deduces the plot just in time, and David and Colby move in and take Crater down before he can kill Polk. However, after learning the whole story from Crater before they take him down, Colby and David meet with a political journalist and blow the whistle on Polk's tactics, effectively ruining his political career.