A 15-year-old teenager is near death after a fight broke out during a rugby match at a Mississauga, Ont. high school earlier this week.

The victim, Manny Castillo, sustained injuries during an altercation at about 4:45 p.m. ET on Wednesday, in the final seconds of the game.

"The altercation that took place between the victim and the suspect wasn't a part of the actual rugby game in itself," Peel region police Const. Adam Minnion told CTV.ca.

"Whether this is a matter of ongoing rivalry, or a conflict between the two, or spontaneous, is something that still needs to be determined," Minnion said.

Castillo, who attended Lorne Park Secondary School in Mississauga, was transported to Toronto's Hospital for Sick Children where he remains in critical condition with a severe head injury.

The coroner has confirmed the victim is not expected to survive.

Homicide investigators have charged a 16-year-old teen from a competing team with aggravated assault.

His name cannot be released under the provisions of the Youth Criminal Justice Act.

The aggravated assault charges could be upgraded should the victim die.

"I'm sure after the requisite evidence is extracted they will lay the appropriate charges," Minnion said.

Crisis counsellors and officials from the Peel board's critical incident response team are on site to help students come to terms with the tragedy.

Students were sent home with letters on Thursday, in which Principal Julie Hunt-Gibbons informed parents of the tragedy.

"We are all deeply saddened and recognize that this is a difficult time for all members of our school community," she said in the letter.

Police have asked anyone with information to contact them at (905) 453-2121, ext. 3205, or to call Peel Crime Stoppers at 1-800-222-TIPS/8477.