Factual error: Agents are staking out a suspect in Boynton Beach, Florida. A truck approaches and they can see the license plate on the front of it. There are no front license plates in Florida. Only rear.
Continuity mistake: In the episode the team is discussing the unsub. He was a man who believed he was Tara's brother. They do not know his name yet. JJ says "He must have put Gabriel's whole life inside of Desmond". Only later does Garcia find out the unsub's name is Desmond Holt. (00:15:22 - 00:18:20)
Character mistake: Rossi reacts upset to the phone call before the killer starts singing happy birthday. (00:06:25)
Other mistake: When Stephen looks at his phone you can see the phone charging symbol even though the phone he's holding isn't charging. (00:06:53)
Continuity mistake: At the end of the episode, the team and their SUVs are spike stripped and then hit by a semi. When the team is shown in the SUVs and when the SUVs are shown hitting the sticks, the SUVs are eleventh generation Suburbans, but when the semi is shown hitting them, they're ninth generation, at least nine years older.
Other mistake: In the opening scene, the car has a Florida license plate visible on the front. Vehicles registered in Florida (and eighteen other states) don't have plates on the front.
Continuity mistake: The same flashback of Roslyn Jareau giving her necklace to JJ is shown twice, but their dialogue is slightly different the second time.
Conspiracy vs. Theory - S17-E5
Plot hole: In order to deactivate the bomb vest, Penelope blocks all cell service in that area. But she reacts positively to the disabling of the bomb back in headquarters, and she keeps talking with the team without restoring cell service.
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