A 34-year-old man died Sunday after running into trouble while swimming in waters off Nanakuli.

The Honolulu Medical Examiner’s Office identified him as Alan K. Kalahiki-Pilialoha Jr. of Waianae.

An exact cause of death is pending.

Police and the Honolulu Emergency Services Department said a man later identified as Kalahiki-Pilialoha was swimming near Mermaid Caves, or “Tunnels,” at about 2 p.m. Sunday when he was swept away by waves.

Bystanders found him floating unresponsive in the water. They brought him to shore and administered cardiopulmonary resuscitation until first responders arrived and took over.

Police said Kalahiki-Pilialoha was taken to a nearby hospital where he was pronounced dead at 3:32 p.m.