Abuse of authority by the captain of a Maritime Self-Defense Force supply vessel is suspected to have been behind the suicide of a crewman in September, sources close to the matter said Tuesday, citing an internal probe.

The MSDF has set up a panel to investigate whether the captain was involved in verbal and physical abuse that could have been related to the 32-year-old ensign's death on the Tokiwa supply vessel, they said.

According to the probe, which is covering about 140 crew members, the captain verbally abused the ensign repeatedly, calling him "stupid" and telling him to "die."