An illegal immigrant who is accused of bringing a stolen AR-15 rifle to his high school and driving a stolen vehicle has been arrested by federal immigration officials after being released by a sanctuary city.

Mario Granados-Alvarado, 18, an El Salvadorian illegal immigrant, was arrested by agents with the Immigration and Customs Enforcement (ICE) after he was released days before by Montgomery County, Maryland, which prides itself on being a sanctuary city.

ICE officials said upon Granados-Alvarado’s release by Montgomery County, they placed a detainer on the illegal immigrant, which requests that the locality keep the suspect in custody until federal immigration officials can take over the case.

“Keeping people safe means not tolerating the release of aliens that present a clear public safety threat back into our communities,” said ICE Field Director in Baltimore 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.”

In March 2014, U.S. Border Patrol agents arrested Granados-Alvarado in Falfurrias, Texas, after he illegally crossed the U.S.-Mexico Border. At the time, he was issued a notice to appear before an immigration judge.

Most recently, though, Granados-Alvarado was arrested after it was discovered that he brought a stolen AR-15 onto the property of Albert Einstein High School, along with a car that he allegedly stole. Police say the illegal immigrant stole the rifle days before from a police vehicle.

Granados-Alvarado is now awaiting deportation.

John Binder is a reporter for Breitbart Texas. Follow him on Twitter at @JxhnBinder.