Last weekend was a bad one for violent crime in Sudbury.

A 27-year-old man was killed in a stabbing at a party in the east end, and a vicious assault in downtown Sudbury has shocked even the most senior investigators.

A late-night attack, caught on camera from start to bloody finish has left veteran officer, Staff Sergeant Rick Waugh, shaken.

“It really sickens your stomach, basically. I couldn't really believe what I was watching." said Waugh.

It was just before midnight September 14th, when police say a fight broke out between two men in a downtown parking lot at the Rainbow Centre mall. Two more soon joined the fray.

Rainbow Centre parking lot, Downtown Sudbury

Waugh says the video then shows the fight escalating, two against one, as the fourth man tried to intervene.

"Brought our victim down to the ground, rendering him unconscious. What can be described as a vicious, brutal attack to a defenseless victim." said Waugh.

By the time police arrived, the suspects had fled, leaving their motionless victim.

He survived, but with a long recovery ahead.

Police say the video they've recovered, and there's more coming, shows more than just the fight. It shows witnesses, a woman and a heavy-set man, someone in a car, who drove off soon after the attack. And that friend of the attackers, who tried to stop the fight, police want to talk to them all.

As for the attackers, police say the first man is six-feet tall with a thin frame and short blonde hair.

The second man is described as six-feet tall and stocky, and was wearing dark clothing and a ball cap at the time of the attack.

Crime Stoppers is offering a minimum $1,000 reward for information.

"The information is always anonymous. 1-800-222-TIPS or they can go online to sudburycrimestoppers.com." said Lise Perreault of Sudbury Crime Stoppers.

"We can't have these people out on the streets. They need to be held accountable for their actions." said Waugh.

Actions that even to the veteran investigator are shocking.