Peabody is an X Middle School Student. He also serves as a Student Council Representative. He has some unknown past history with Fillmore, and mistrustful of the supposed reformed Safety Patroller.
When the school term papers were stolen and the perpetrators keep eluding the Safety Patrol, Peabody was grilling Valejo hard and made a derisive comment towards Fillmore for leading the investigation.
As the investigation showed no further leads, Peabody continued yelling at Valejo and grew more angry that Fillmore was fraternizing with his former criminal associate, Sonny Lombard. Fillmore defended Sonny before Peabody, stating that he's at least doing something. Peabody vowed to keep his eye on Fillmore.
Peabody later got an anonymous phone call tipping him to off to Fillmore bootlegging fake hall passes. He finds the hall passes in Fillmore's desk, which made him assumed that he isn't as reformed as he claimed. Vallejo was skeptical, believing that Fillmore wouldn't be caught dead, but nonetheless, Peabody took the matter to Principal Folsom and ordered Valejo to suspend him. Fillmore later came with evidence that Sonny was the one who called Peabody and planted the phony hall passes in his desk, all part of the plan to get Fillmore to raid the Home Economics department without a warrant to get the term papers from Rudy Teravall, having been provided Sonny's cellphone with its call history. Peabody then retracted his accusations and signed the warrant. He later stood by Vallejo and O'Farrell at the end of a radio, in which Fillmore was obtaining a confession from Sonny. Once Sonny is apprehended, Peabody formally announces to the school papers about the successful recovery of the term papers.