Ontario's police watchdog is investigating after a man fell to his death in a No Frills parking lot in Newmarket.

The S-I-U says it happened at about seven o'clock Sunday evening.

It says the man had reportedly been causing a disturbance at the grocery store.

When officers arrived, the agency says that the man was standing on a ledge roughly nine metres from the ground in the parking lot.

It says the man fell to the ground a short time later and was pronounced dead after being taken to hospital.