WASHINGTON — A Silver Spring, Maryland, teen charged with bringing an assault rifle to his high school was released on bond despite having an Immigration and Customs Enforcement detainer in his name.

Montgomery County police arrested Mario Granados-Alvarado, 18, at Einstein High School in Kensington, Maryland, on May 3 after finding an AR-15 in his car trunk, which they said was stolen from a Rockville police cruiser.

Facing weapons charges, he was released on bond from the county detention center on May 3.

But ICE agents placed a detainer on the El Salvadorean national the day before, according to ICE. The federal agency said Granados-Alvarado should never have been released.

The county has “publicly limited cooperation with ICE and frequently ignores legally authorized detainers,” ICE said in a news release.

“Keeping people safe means not tolerating the release of aliens that present a clear public safety threat back into our communities,” said Enforcement and Removal Operations Field Office Director Dorothy Herrera-Niles said in a statement. “ICE is committed to fostering positive collaboration with our local law-enforcement partners, and welcomes changes from county officials that would prioritize public safety.”

ICE officers brought Granados-Alvarado back into custody May 4 and say he is in removal proceedings.