A Maritime Self-Defense Force sailor who died last month may have been made to undergo an excessively punishing exercise at an MSDF special forces academy, Defense Minister Yasukazu Hamada said Oct. 14.

The incident has also raised the possibility that retaliation occurs in training against those who are seeking to leave the special forces school.

"Given the circumstances we are aware of, I don't deny that I feel there was something special or unusual" about the case, Hamada said, pledging to get to the bottom of the incident.

The 25-year-old petty officer third class died Sept. 25 after being forced to fight 15 opponents as part of his training with a special MSDF task force at the force's First Service School in Etajima, Hiroshima Prefecture, on Sept. 9, according to the MSDF.