As the murderer continues his murder spree with Detective Speicer's daughter as his hostage the team do everything they can to catch him.

While JJ attempts to reunite a family whose daughter has mysteriously disappeared, her BAU family braces for the loss of one of their own

When several women are found murdered in a similar fashion, Rossi revisits a cold case that has haunted him for 25 years, causing him to suspect that the original killer is at work again.

Because of JJ's departure Hotchner is looking for someone from the team to take over her duties, meanwhile, the team is searching for a serial killers who goes after married couples.

The BAU team is on the trail of a serial killer targeting families throughout the Midwest. Meanwhile, Morgan is concerned when Ellie runs away from her foster family and pays him a visit.

For the past three years a killer has been active in Detroit during the pre-halloween celebrations, but this year the BAU is there to catch him.

As bodies of exotic dancers start turning up in the middle of cornfields in Indiana the BAU is called in to help the local sheriff.

When a kidnapped woman is found murdered in an alley in Georgetown, the BAU team goes on the hunt for the killer before he can strike again.

When an 8-year-old is found murdered on the Appalachian Trail, the BAU team goes deep into its forests in search of a man lurking in the wilderness who is targeting children

The BAU searches inside a gated New Mexico community for a killer targeting women, and Hotchner looks to an FBI cadet with a unique past for help with the investigation.

Morgan believes a prisoner has been rehabilitated and helps him get paroled, but soon regrets his decision as the man murders someone.

As the BAU travels to Miami to investigate a series of bizarre, ritualistic murders, Reid suffers a series of blinding headaches and hallucinations that leave him concerned for his health.

The BAU hits the road to track down a pair of young lovers on an interstate murder spree. Also, Prentiss hears frightening news from her former boss at Interpol.

The BAU travels to Los Angeles to investigate unusual murders throughout the city. Also, more of Prentiss' mysterious past comes to light.

The BAU is called to upstate New York to investigate mysterious disappearances. Also, Prentiss gets some disturbing news about one of her former Interpol colleagues.

Reid makes a connection with an autistic child that could assist the BAU in finding the boy's missing parents. Also, Prentiss enlists two former Interpol colleagues in hunting an old nemesis.

After a series of suspicious murders occur, Prentiss suspects her old Interpol nemesis, making her fear for the safety of her BAU team as he closes in on her.

Prentiss is ready to confront her nemesis, Ian Doyle, once and for all. Meanwhile, the BAU calls upon JJ to help them find Prentiss and capture Doyle before it's too late

When a gang of suspected murderers begins targeting a new victim each night, the BAU travels to Portland to head them off before they can strike again.

As the BAU investigates targeted killings in Tampa, they also deal with their own feelings about the loss of Prentiss

The BAU hunts a stalker in San Diego who is targeting college students. Meanwhile, the team comes under Strauss' scrutiny in the wake of the loss of Prentiss.

The BAU is called to a North Carolina mountain town after a woman is found badly injured and another is missing, and they discover that these two are not the only victims.

In season six episode twenty three(s6e23) the behavioral analysis unit this time moved to florida as they were compelled to investigate over a case in which the human dead bodies were found to be floating over the ocean floor of Jacksonville. Meanwhile the case takes a steep turn when Morgans aunt complains that her missing could also be one of the victims.

The bodies of two missing persons are found in a car trunk, and the BAU suspects that an interstate human trafficking ring is at work. Also, Hotch warns the team of possible changes, and they are surprised when a beloved team member returns.