Updated 04/04/14 – 10:59 a.m.

CHICAGO (CBS) — A 22-year-old man was arrested Thursday morning, after allegedly impersonating a U.S. Marshal when he was found wandering the halls of a South Side high school carrying a gun, wearing a bulletproof vest, and carrying a stolen security agency badge.

Police said Brandon Salvatore, of Richton Park, has been charged with one count of false impersonation of a federal employee, and one count of aggravated unlawful use of a weapon without a concealed carry license. He was arrested at 11:15 a.m. Thursday, after he entered Percy L. Julian High School, 10330 S. Elizabeth St., while carrying a loaded firearm, and claimed to be a federal marshal, but could not produce proper identification.

Bond was set at $10,000 for the alleged intruder. He was released Friday and declined comment.

Sources said he was wearing a bulletproof vest, had a handgun in a holster, and was carrying a badge he’d stolen from MJM Security Agency, based in Richton Park. Although he works for the security company, he was not authorized to have a badge. He also had loaded ammunition clips with him.

He’s now been fired. An attorney for the company said in a statement: “Mr. Salvatore obtained materials he was not authorized to have and the company is investigating that.”

MJM also says Salvatore was not on duty when he showed up at the school.

According to sources, Salvatore got past security at the school, and was stopped by a police officer who found him roaming the halls.

Many parents and students interviewed by CBS 2’s Courtney Gousman said they did not know about the incident until she informed them about it.