|“||Daddy! Help me!||”|
— Joe to his father, Landon, as he is being arrested
Born with some unspecified mental handicap, Joe worked at a traveling carnival run by his father, Landon, doing menial chores and dressing as a clown to try and entertain visitors. When the carnival passed through Indianapolis, Indiana in 1988, Joe grew attached to young Connie Galen, who he had given a poorly-made balloon animal. Wanting to play with her, Joe began to follow Connie around the grounds, worrying Connie's parents, Richard and Diana, who decided to leave early. While his father was busy working on a malfunctioning ride, Joe took off, somehow tracked the Galens down to their home, and broke inside, intent on finding Connie in order to play with her. Mistaking the parents' room for the children's, Joe entered and accidentally woke up Richard, who hit him with an ax. Growing angry and scared after being hurt, Joe took the ax from Richard and used it to kill both him and Diana.
Instantly regretting what he had done, Joe placed the couple's bodies back in their bed just before his father found him. Landon, having found out what Joe had done, managed to remove all the evidence Joe had left, except for one fingerprint, which would prove useless to the authorities anyway since Joe wasn't in the system. To punish Joe for what he had done, Landon would have the carnival pass through Indianapolis around the same time every year, to remind his son of the murders. While in town, Joe would drop some carnival prizes off to the Galen children. The children assumed the gifts were delivered by Rossi, who by sheer coincidence happened to be one of the first to respond to the Galen residence after the murders, following his closure of another case at the time.
Back in Indianapolis, twenty years after the murders, Joe drops some presents off to the Galen children once again, though this time he goes as far as putting a stuffed animal in Connie's car while she is working. The day after, Joe drops the presents off as the carnival begins to pack up, with Joe helping out by cleaning up trash. When the BAU, who are investigating the Galen murders, arrive at the carnival, Joe runs and hides when he sees Morgan and JJ approaching. Following a trail of garbage, Joe has accidentally left behind, Morgan and JJ find him cowering under a large vehicle and pulls him out. While being arrested, Joe begins weeping, crying out to his father, who can only look on helplessly as his son is taken away. Due to his mental state, he is undoubtedly placed in a mental institution.
Due to the amount of overkill present in the Galen slayings and the fact that an incidental object was used as the murder weapon and witnesses were left behind, the unsub is classified as a disorganized killer by the BAU. Gifts being sent to the family of the victims indicates the killer is filled with remorse while the kind of gift (cheap toys such as stuffed animals) indicate the unsub may have a childlike mentality and committed the murders unintentionally. This type of offender tends to be developmentally disabled, physically large, very strong and have an extremely low I.Q. He is likely controlled by and taken care of by an older relative who tries to keep the unsub in line, rationalizes what he did, believes he would never try to hurt anybody, and cleans up after him. He may have committed lesser offenses in parks and playgrounds, which involved children who were never hurt or abused.
Since Joe killed two people in one attack, the term "M.O." is misused. He killed the Galens with an ax he took from Richard, an act that was provoked after he was scared and angry after being chased and hit with the weapon.
- 1988: Richard and Diana Galen
- A sign reading "Legacy" is prominently displayed several times at the carnival Joe's father owned; at one point it is partially obscured, causing it to read "Gacy". John Wayne Gacy was an infamous serial killer who also happened to work as a clown.
- Season Three
- Season Four
- "Omnivore" (referenced)
- Season Twelve
- "Green Light" (indirectly referenced)