The body of a 20-year-old man, covered by a blanket, lies on the street after he was crushed by the wheels of a float during the annual Montreal St. Patrick's Day parade. (Graham Hughes/Canadian Press)

Organizers of the St. Patrick's Day parade in Montreal say they will look at improving security after a 20-year-old student was killed during the annual event Sunday.

Alexandre Hamelin of suburban Laval jumped off a flatbed truck and slipped under the wheels at about 2:15 p.m. ET near Ste-Catherine and Metcalfe streets, police said.

Investigators said they believe alcohol was a factor in the incident, which happened two hours into the event.

Hamelin was one of two young men who jumped on a shamrock-decorated float belonging to a local college, police said. The death apparently happened when the two later decided to hop off the Marianopolis College float.

Hamelin was pronounced dead at the scene, and thousands of spectators were dispersed by police.

Montreal police spokeswoman Anie Lemieux said the second young man was treated for shock and will be questioned by investigators.

Drinking witnessed

Lemieux also said witnesses had seen Hamelin drinking.

Public drinking is a tradition during the St. Patrick's Day parade in Montreal. Spectators along the route can be spotted openly drinking beer and whisky during the cold March celebration.

But organizers discourage alcohol consumption, said Gerald Showers, spokesman for the United Irish Societies of Montreal.

"We really try everything we can to dissuade anyone from going that route," Showers said.

Organizers will wait for the final police report before making any decisions about possible parade changes, Showers said.

He said it was too soon to consider banning motorized vehicles from future parades — a measure that has always been in place for St. Patrick’s Day parades in New York City.

Hamelin was a student at Montreal’s St. Pius X Culinary Institute, where staff were helping students deal with their grief on Monday.

Vice-principal Saverio Servello said he has fond memories of Hamelin.

"He was a very polite, well-spoken — always had a smile on his face," Servello said.

In 2002, a Concordia student slipped under the wheel of a parade float and crushed his legs.

The Montreal parade, one of the largest in North America, has been held annually since 1824.

With files from The Canadian Press