The Behavioral Science Unit's killer instincts move from theory into action when the FBI joins in a high-profile hunt for a serial child murderer.

Amid sweeping changes at the BSU, Holden deals with severe repercussions from his close encounter with Ed Kemper.

To glean insight into the elusive BTK killer, Bill and Holden interview the Son of Sam, who makes a startling admission.

Bill gets drawn into a horrifying crime that hits close to home. Holden receives an intriguing offer while in Atlanta to interview a pair of killers.

Holden develops a controversial profile in the Atlanta slayings. Wendy conducts her first interview and finds being on the front lines suits her well.

Bill's devastating family situation spills over during his interview with Holden's holy-grail subject: Charles Manson. Wendy's new romance heats up.

The FBI officially sends the BSU to Atlanta to investigate the missing and murdered children. Wendy second-guesses her interview methods.

Hitting a dead end, Holden suggests a bold plan to draw the killer out. Bill's family faces more scrutiny. Wendy chafes as her job begins to shift.

Red tape hinders Holden's plan to narrow his suspect pool. A weary and heartsick Bill tries to connect with his son. Wendy rethinks her relationship.

The investigation zeroes in on a prime suspect who proves surprisingly adept at manipulating a volatile situation to his advantage.