The death of a fan during the New England Patriots vs. Miami Dolphins game at the Gillette Stadium last Sunday sparked an investigation from the Massachusetts State Police.

Dale Mooney, a 53-year-old man, passed away after he had an apparent "medical event" while sitting at the 300-level of the stadium during the fourth quarter of the game.

Emergency medical technicians rushed Mooney to the Sturdy Memorial Hospital, where he was pronounced dead.

The Norfolk District Attorney's Office said investigating the death is part of "normal protocol."

Mooney has been a season ticket holder of the Patriots for the past 30 years, and he leaves behind his wife, Lisa, and two adult sons.

"We are heartbroken to learn of the tragic passing of Dale Mooney, a lifelong Patriots fans and 30-year season ticket member, who died while attending last Sunday night's Patriots game," Gillette Stadium officials said.

The statement added that they continue working with local authorities to assist them with their ongoing investigation.

Violent confrontation happened

A witness claimed a violent confrontation happened just before Mooney's medical event.

Patriots fan Joseph Kilmartin, who was in attendance, said he witnessed Mooney grab another fan.

"They started tussling around for a few minutes. At one point, another fan walked over. He punched him ... and the man just went out. It was pretty hard to watch," Kilmartin said, as reported by CNN.