A St. Paul man allegedly attacked a 79-year-old man on a light-rail platform Monday evening, slamming him against a glass wall, punching him several times and taking off with his groceries.

Eric G. Larson, 44, was charged Wednesday in Ramsey County District Court with one count of first-degree aggravated robbery for the attack at the Green Line's 10th Street station in downtown St. Paul.

The elderly victim suffered bruising and swelling on his right arm and the left side of his face, and his $300 prescription glasses were broken.

According to the complaint: Metro Transit officers were patrolling the Green Line when they spotted Larson about 7:11 p.m. swearing on the platform. A witness told the officers that Larson had attacked an elderly man.

Officers found the victim, who said he had set a bag of groceries down so he could buy a light rail ticket. Larson grabbed the bag, the man told officers, and refused to return it.

"They're not yours anymore," Larson allegedly said.

The victim told officers that he tried to get his groceries back, and Larson pushed him against a glass wall, punched him several times and threatened to throw him on the tracks, the complaint said.

"It's not your day, old man," Larson allegedly said.

Officers arrested a combative Larson at the scene, according to the complaint.

Surveillance video captured the attack, and also showed bystanders rushing to the victim's aid.