Montreal police said the man may have been in the pool partying after hours when he got into trouble.
Police were called to the pool in Alexis-Carrel Park in Rivière-des-Prairies at around 4:20 a.m. after receiving a report about a possible fight in the park.
When they arrived, they found one man who appeared to be in shock screaming and another man unconscious in the pool.
Officers pulled the man from the water and started live-saving measures before the man was taken by ambulance to hospital.
Police are now investigating the incident and said it’s unclear how many people may have hopped the fence to the closed pool.
“We know that they were possibly there to party. [It is] possible alcohol was involved in that sad accident,” said Const. Raphaël Bergeron.
“It appears the festivities turned really bad.”