The Girl In The Blue Mask
Criminal Minds: Suspect Behavior Season 1 Episode 12 (05/18/11)
The episode opened with a wounded hiker stumbling out of the woods into a camp site with half of his face missing. The hiker died due to blood loss as it appears someone attacked him and took part of his face.
Cooper and his team are called in as the attack was very close to the FBI headquarters and on military base in a large park area. Garcia finds there was another victim a few days earlier just outside the military base.
The team quickly figured out that the unsub is attempting to harvest skin for some form of transplant as he is only taking a small amount and always from the face. Shortly after this, a third victim is found who is alive. She told Cooper the man mumbled something about keeping his promise.
Gina begins to take the case very personally as she is having difficulty with her own father and can identify with the unsub's target she believes to be his daughter. After a 4th victim is taken from a bakery alive the team discovers a cake for "Kristi Anna" is missing as well.
Garcia using the name Kristi Anna finds a four year old case where a father had kidnapped his daughter from his divorced wife and had taken her into the ER with burns on her face. He got away and had not been seen. Garcia found he had rented a house close to the attack area.
The team raided the house saving the girl who had been kidnapped. Gina stayed with the daughter as the EMT went to check out her injuries under the mask she was wearing. When she took off the mask, her skin was fine; it had healed without even a scar.