Windsor police say a 15-year-old is in the intensive care unit after being beaten.

Police say the teen was assaulted by four people in a Marentette Avenue apartment at about 7:30 p.m. Monday night.

When police arrived, the victim was unconscious. He was breathing but unresponsive. Police said his face was bruised and swollen.  He was bleeding from his nose.

He was admitted to the ICU with a brain bleed and remains in in serious condition, according to police.

Four suspects have been arrested. They include a 15-year-old female, a 16-year-old female, a 17-year-old male and a 20-year-old male. All face charges of aggravated assault.

The investigation is being handled by the Windsor Police Service's major crime branch. The investigation is still in its preliminary stages. 

Detectives are interviewing witnesses and trying to determine the motive for the assault. 

Police are asking anyone with information to call.