The flag at Glebe Collegiate high school in Ottawa was lowered to half-mast Monday after a student died in a cliff jumping incident at an eastern Ontario lake over the weekend.

Police divers located the body of 15-year-old Hay Mu Tha Ku in Charleston Lake, west of Brockville, on Monday.

Ku, a Grade 9 student at Glebe Collegiate in Ottawa, failed to resurface after jumping off a cliff at the lake early Saturday evening.

Police say Ku was swimming in the area with two other young males at about 6:45 p.m. Saturday.

It's believed Ku jumped off Indian Head cliff, a popular diving spot at the lake. But after jumping, he never resurfaced.

Emergency officials, including the OPP marine unit, were called to the scene Saturday, but were unable to locate the teen.

The OPP's Underwater Search and Recovery Unit was later called in to take over the investigation. The dive team discovered Ku's body on Monday, near the spot he was last seen.

Police say a post-mortem will be scheduled at the Ottawa hospital.

Ku was on his high school volleyball team, and usually hung out with kids in Grade 11. Students say he was known simply as "Hay."

The principal at Ku's high school says students became very fragile when they learned about his sudden death.

Grief counselors are on hand to help staff and students deal with their loss.

The last day of regular classes at the school was Monday. Exams are scheduled to start on Tuesday.