A man with a loaded handgun, wearing a bullet proof vest and carrying a bag of SWAT equipment authorities believe was stolen from New York City police has been arrested at Chicago's busiest train station.

Chicago police say 21-year-old Isaiah Malailua was arrested Friday morning at Union Station ticket counter and charged with unlawful use of a weapon for wearing body armor.

Cook County Judge John Fitzgerald Lyke set bail at $100,000 and ordered Malailua, from Redding, California, to remain in the Chicago area.

Isaiah Malailua, 21, of Redding, California, was arrested at Chicago's Union Station Friday morning

A police dog smelled explosive residue on the young man's duffel bag, which was found holding stolen NYPD body armor. Above, a view of Chicago's Union Station

Lyke says: 'This is troubling, to say the least, in light of what's happening in our country.'

Malailua was arrested around 9:30am, after Amtrak police dogs sniffed explosive residue in an unattended bag, the Chicago Sun-Times reported.

Officers found materials with NYPD SWAT patches inside and a bus ticket for Malailua. He was traveling through Chicagom but police have not said where he was headed. Illinois state law bans anyone possessing body armor if they don't have a state firearm owner's ID card.

At the time, Malailua was wearing a bullet-proof vest and carrying a loaded Taurus brand 9mm pistol. Prosecutors say he doesn't legally own the gun.

In a statement to ABC 7 on Sunday, the NYPD said they 'are aware of the incident and are working with authorities in Chicago'.

Malailua's next court appearance is on Friday.

Public records show he has a criminal history in Florida.

This is the second time in a little more than a month that a man was arrested in Chicago while wearing bullet-proof armor.

on February 13, Shomari Legghette-a, a four-time felon, was arrested after he used a pistol to shoot and kill CPD Commander Paul Bauer inside a stairwell at the Illinois Thompson Center.

No shots were fired in Malailua's arrest on Friday.