The Royal Canadian Mounted Police in Prince George were alerted Monday to the discovery of an unconscious man in a snowbank behind an apartment building, CBC News reported.
One RCMP officer said the man was the victim of "a horrific sexual assault."
Investigators then learned a second youth was also assaulted.
"Police have determined that the victims were targeted and lured to the apartment building where they were assaulted by a group consisting of both youths and young adults," Cpl. Craig Douglass said.
Over the next two days, investigators arrested six people -- a 20-year-old female and the teenagers, one of them an 18 year old male. The other four teens are three males and a female.
"This is a very disturbing investigation. We will do everything we can to bring those responsible to justice," Douglass said.
One of the victims remained hospitalized in serious but stable condition, CBC News said.
Jessica Simpson shares three-way kiss with friends in photo
Teacher apologizes for showing sexual image of herself in class