Quebec Police say a man in his sixties has died after suffering a heart attack near one of the entrances to Montebello's Rockfest. 

The Sûreté du Québec said the Brockville man was found lying on a sidewalk near Notre-Dame and des Mille-Fleurs St around 11 a.m. Saturday, June 24. Police say the man was in Montebello attending the rock festival with friends.

Mark Decotret was working at the campsite when he heard a commotion.

"He just sort of fell over," Decotret said. 'Everybody was there. Everyone was in a panic. People were crying and they were really upset." 

Decotret said everyone in the area came rushing over to help. He says bystanders called 911 and started CPR until paramedics and police arrived.

'It's just so sad," Decotret said. 

Organizers of Montebello's Rockfest said extra security and emergency responders were brought in this year to help keep festivalgoers safe. 

"They are here so if anything happens, they are on site and here to intervene," said Mathieu Marcotte, a spokesperson for Rockfest. 

Marcotte said the man's death has shaken everyone involved in the festival. 

"It's just so sad because he was obviously here to party, here to have a good time," he said. " You never want something like that to happen."

The Sûreté du Québec do not believe the man's death is suspicious nor criminal. An autopsy is being performed to determine what caused the man's heart attack.

"As an organization and as a human being and a music enthusiast, it's something that really saddened me," Marcotte said.

The man's identity has not been released. 

Rockfest wrapped up Sunday night. Tens of thousands of people were estimated to have travelled to Montebello for the rock festival, which this year featured 130 performers.