A 19-year-old man drowned after getting into trouble during a party boat trip off Sai Kung on Friday afternoon.

The teenager had entered the water down a slide from the vessel at about 3pm. A police source involved in the investigation said: “He developed cramps and shouted for help before going under. His friends searched but failed to find him.”

Divers from the Fire Services Department searched the waters of Tai She Wan, off Sai Kung East Country Park, and after about 90 minutes found the man on the seabed about 10 metres down.

A police spokeswoman said he was airlifted unconscious by a Government Flying Service helicopter to Pamela Youde Nethersole Eastern Hospital in Chai Wan, where he was certified dead.