DEDHAM, Mass. (AP) — A man who died at a New England Patriots home game last weekend was punched at least twice in the head during a fight in the stands with a rival fan, a witness said Tuesday.

Police and safety personnel responded to the upper deck at Gillette Stadium shortly before 11 p.m. Sunday and found Dale Mooney, 53, of Newmarket, New Hampshire, “in apparent need of medical attention,” the Norfolk County District Attorney’s Office said in a statement Monday.

Mooney was taken to a hospital, where he was pronounced dead. The Massachusetts State Police are investigating what the district attorney termed an “incident” at the stadium.

Witness Joey Kilmartin shot video of what he said was a brutal fight.

In interviews with several local media outlets, Kilmartin said he saw Mooney, a Patriots fan, confront a Miami Dolphins fan who he had been arguing with during most of the game, which the Dolphins won.

“He basically engaged in mutual combat with another fan,” Kilmatin told The Boston Globe. “A lot of people started trying to pull them apart. … It looked like somebody was in the middle of them, and then a man in the Dolphins jersey reached over and he connected with two punches to the victim’s head.

“It wasn’t something crazy or out of the ordinary until, 30 seconds later, the guy wasn’t getting up.”

The results of an autopsy were expected this week, a spokesperson for the district attorney’s office said.

Mooney’s wife, Lisa Mooney, said she feels numb and wants answers about how her husband died.

“I just can’t even believe this is for real,” she told WCVB-TV. “I want to know what happened. What caused this?”

Gillette Stadium officials said they were “heartbroken” by the death of Mooney, who they described as a lifelong Patriots fan and 30-year season ticket member.

“We continue to work with local authorities to assist them with their ongoing investigation,” according to the statement. “We extend our sincerest sympathies and heartfelt condolences to Dale’s family and to all those who are mourning his loss.”

Fan violence at sporting events, especially among rival supporters, is a long-running problem. Among the most infamous was the 2011 Dodger Stadium parking lot beating of Bryan Stow, a paramedic and San Francisco Giants fan.

Two Los Angeles Dodgers fans punched Stow, who fell to the pavement and suffered severe head injuries. He was awarded about $14 million when a jury found the team was negligent. The attackers received prison sentences.