Visible crew/equipment: When JJ and Derek get to the bar to talk to Harris Townsend, while they're still outside in the parking lot, right after Derek tells JJ not to turn her back on the door, the reflection of the moving camera can be seen on the pickup's back window as they walk to the door.
Visible crew/equipment: When the trailer park manager leads Rossi and Reid to Goehring's trailer, right after he tells Reid, "Piece of advice, pipe cleaner, way you're wearin' that gun...beggin' someone to take it off you," the cameraman and camera cast shadows on Reid as he walks by the camera.
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 his 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