Won't Get Fooled Again - S1-E3
Other mistake: Just after they were finished explaining that you can not tilt the mystery package because it would instantly blow up, they show the little girl at her doorstep holding the package completely tilted. Just when you think that means that this package now doesn't fall into the "explosive" category, they then show the mom freaking out, and later police making the girl hold the package in a completely different (non-tilted) position.
Won't Get Fooled Again - S1-E3
Audio problem: The video game Penelope is playing is supposed to be Tetris, but the sound effects are from the Atari 2600 version of Pac-Man. You can hear Pac-Man die four times during the scene. (00:12:20)
Won't Get Fooled Again - S1-E3
Continuity mistake: When talking to Bale in jail and negotiating a transfer deal, his handcuffs disappear and reappear between shots. (00:35:05)
Won't Get Fooled Again - S1-E3
Continuity mistake: When in the house and the victim's wife comes in, Hotch returns his ID to his pocket twice. (00:08:00)
Answer: "The Boogeyman", s02e06. Spoiler alert: The kid is Jeffrey Charles and at that point he had already killed 3 other kids. Jefferey basically hated and resented other kids after his mother abandoned him and his father spent a lot of time with other children because of her job. Jeffery would lure kids Into the Woods and then beat them to death with his bat just because of hate, no particular "reason." The scene you're describing, Jefferey agrees to walk Tracy home when her "buddy" leaves her (at this point the FBI announced there's a serial killer on the loose and kids should walk with a buddy). Jeffrey gets mad at Tracy for walking too slow and for complaining, and he takes a swing at her, causing her to flee Into the Woods and have Jeffery chase her.
Bishop73