Chris Warren Gilbert

When a man in full clown costume shoots a bakery owner, the CSIs investigate and discover a decision from Flack's past that may put him in jeopardy. (TV-14)

Eric Delko returns as an expert witness for the defense, pitting himself against his old team.

During the murder investigation of a state senator, Don and his team discover a plot to exact revenge on the individuals involved in a government sponsored behavior modification project. Though the program was discontinued, Don and the FBI learn that someone is still able to make the conditioning work on former subjects and is using them to commit murder. Meanwhile, Larry announces he is taking a leave of absence from the university to travel on the next space station crew rotation.