The incident began around 3 a.m. Saturday when Colin McGovern and three friends made a passing remark to a man wearing a Devils hat, according to police. An argument broke out between the man, 40-year-old Steven Simminger, and McGovern, and eventually escalated to a physical altercation.

MORE: Notable sports deaths of 2016

First responders found McGovern on the sidewalk with multiple stab wounds to his torso. He was taken to a hospital, where he was pronounced dead.

“This was over a hockey cap,” Philadelphia police Capt. James Clark said, via The Associated Press, calling the altercation “very senseless.”

Simminger, who lives in New Jersey, took himself to a Veterans Affairs hospital for treatment of a cut on his hand and told doctors he had been involved in a fight, Clark said. Police learned of his whereabouts and made the arrest, charging Simminger with murder and related offenses.

Clark said Simminger also underwent a mental evaluation at the hospital.