"Yes, sir. I mow the lawn, sir. And now you want me to mow your lawn, sir?"
Lyle was born to Charles and Tina Johnson, although it turned out that he wasn't naturally conceived between them due to a castration attack his father suffered during his teenage years. Lyle was apparently conceived through the aid of a sperm bank. In his early years, he had a short temper, which resulted in bursts of rage and sometimes acts of violence, one of which involved throwing a television set at his mother's head. In 1978, when he was five years old, Lyle may have witnessed Charles killing one of his victims, but repressed the memory. In his adult years, Lyle dated a schoolmate named Mary Ann Beck, but in 2003, she mysteriously disappeared. Unbeknownst to him, Charles had murdered her and then buried her body in the family backyard, since Mary Ann was the daughter of one of the men who castrated him. Later on, after a string of failed jobs at fast-food restaurants, Lyle decided to follow in his father's footsteps and became a contractor, working in his father's construction company, J&J Contractors. Sometime during his life, he came across a stash of testosterone pills kept by his father to deal with his castration; Lyle subsequently began taking the pills as well.
In the episode, Lyle and Charles return home from their work, only to find the BAU and police searching their house and digging up the family backyard as Tina tries to reason with them. When Hotch identifies himself as an FBI agent, Lyle immediately runs away and nearly evades capture, being pursued by Hotch. When he tries to climb over a fence into another backyard and is confronted by a dog, he immediately surrenders. As he is taken to an interrogation room, Lyle begins ranting about how the FBI was intentionally arresting him and his parents without justifiable cause. Because of his behavior, the BAU suspects him to have killed Mary Ann and another woman in 2003, whose skeletons were found in the backyard after a drainage pipe exploded and flooded the backyards of several houses. JJ and Cruz interrogate him, and Lyle begins acting aggressively while defending himself from the accusations, up to the point where he tries to angrily break free from the cuffs chaining him to the interrogation table. At the house, Reid and Blake discover Lyle's stash of testosterone pills and assume that they have contributed to his hostile personality.
Later, one of the skeletons found is identified as Mary Ann and the connection between her and Lyle is traced, to which JJ and Cruz tell him about it, assuming that he killed her out of rage, and then moved on to the second victim because she was physically similar to Mary Ann. However, upon finding out that Mary Ann was dead, Lyle begins to break down, but despite his reaction to Mary Ann's identification, the BAU continue to assume that Lyle was the killer, believing his grief to be a sign of remorse for her death. However, when a third skeleton belonging to a male is found in the Johnson backyard and deduced to have been killed in 1978, when he was still a child, Lyle is let off the hook. He later expresses rage when he finds out that the investigation has shifted its focus onto his parents. By the end of the episode, it is revealed that Charles was the killer, having been targeting the men who castrated him and then the daughters of the assailants he was unable to attack. Lyle is last seen sitting beside his mother on a bench and is approached by Rossi, who looks at them remorsefully before walking away without saying another word.
- ↑ Though that had been implied several times throughout the episode, this was never explicitly confirmed