Police later said the boat capsize was caused by the wake from a fishing boat heading in the opposite direction near Royal Bay Commercial Centre, Jalan Buruh Bintawa, here.

The five missing participants are Ikhmal Sama’ail, Majurie Maharuf, Afiq Isyamudin Asaari, Khairul Bidin and Khairul Hisyam Kasturi, aged 22 to 35.

District police chief Farhan Lee Abdullah said the 16 participants were staff of the Sarawak Security and Enforcement Unit.

Farhan said the search began at 4.37 pm and ended at around 7.30pm. It would resume at 6.00 am tomorrow, and will be concentrated in two areas.

“We will be assisted by local fishermen and we urge those who wish to help to be coordinated by the police,” he said, as he advised the public not to speculate on the incident.

Farhan said that the participants were training for the highlight of the Sarawak regatta and Kuching waterfront festival on Nov 1-3.