The 16-year-old was released to a family member earlier this week. But he was sent to the Middlesex County Juvenile Detention Center after a court hearing on Thursday. He'll remain there until a new hearing next Friday.
Police investigating recent bomb threats at Edison High School searched the boy's home. Officers said they found fireworks, shotgun shells and makeshift devices containing gun powder and fuses.
Authorities say there's no evidence linking him to the bomb threats and officials are not planning to file more serious charges.
His name has not been released because he's a juvenile.