Visible crew/equipment: When James Charles, the guidance counselor, says, "It could be someone you know, or it could be a stranger you pass at the grocery store," the actors' red T-marks are visible on the floor at Reid's and Gideon's feet. Then when Charles continues to say, "gathering information on the case," we can also see the actor's white T-mark beside the counselor's feet, where he will stand after he introduces Gideon.
Continuity mistake: When the team is profiling the unsub, Reid's watch goes from being under his sweater's sleeve to being over it.
Continuity mistake: When Garcia accesses the bank's page online Prentiss gives her the account number login, 1552 9384 6729, and we see Garcia typing it correctly on the screen with the password, but when it cuts to the account's page showing deposit and balance, we see in the balance box the account number's last four digits are 7629, not 6729.
Continuity mistake: When Morgan gets off the phone after talking with Garcia about the list of chemicals he found, the hand holding the phone to his ear changes between shots. (00:13:55)
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