A teenager is in custody in connection with the small explosive devices that were found on a Waseca, Minnesota, elementary school's playground back in March, according to a release on the school district's website.
Police arrested a 17-year-old boy Tuesday night after the Bloomington bomb squad executed searches at a home and storage facility in Waseca.
In March, officials discovered three explosives, two that were detonated and one that had failed to detonate, on the playground of Hartley Elementary School.
Officials had described the devices as “small compressed air cartridges similar to those in a BB or pellet gun."
No one was injured, but parents were upset that officials didn't notify them right away.
Felony charges are expected to be filed Thursday and a press conference with police and the school is scheduled for later that day, KSTP reports.
The suspect remains in custody pending an initial court appearance.