Sri Lanka’s first sailor to successfully complete the United States Marine Corps’ Basic Underwater Demolition/SEAL (BUD/S) training, Lieutenant Mahavithanage Don Koyan Chamitha, has passed away following a suspected heart attack, the Sri Lanka Navy confirmed.

The Navy said the 28-year-old officer was found dead at the naval quarters within the Welisara Navy Camp. His death was also announced in a post shared on his former school’s official Facebook page.

Lieutenant Chamitha, a resident of Gampaha, made history in July 2025 when he became the first Sri Lankan sailor to complete the elite SEAL training programme in the United States. Following his return to Sri Lanka, he resumed active naval duties.

Investigations are currently underway to determine the exact cause of death.

Meanwhile, Secretary to the Ministry of Defence, Air Vice Marshal (Retd.) Sampath Thuyacontha, has directed the Commander of the Sri Lanka Navy to conduct a formal inquiry into the circumstances surrounding Lieutenant Chamitha’s sudden passing and to submit a detailed report.