Photo/IllutrationThe Maritime Self-Defense Force refueling ship Tokiwa (Provided by the Defense Ministry)

A Maritime Self-Defense Force officer who killed himself aboard a refueling ship had been repeatedly bullied by his superiors, sources said, quoting a survey of crew members.

The Maritime Staff Office sent questionnaires to all 140 or so crew members of the Tokiwa after the 32-year-old ensign committed suicide in September, the sources said.

His body was discovered on the Tokiwa at the Yokosuka Naval Base in Kanagawa Prefecture. A suicide note was not found.

According to the survey results that quoted witnesses, the captain had prohibited the ensign from taking a rest while another superior officer refused to let him go home.

Another superior told the ensign, “You should die” and “You should disappear.” On the night before the suicide, the superior threw a binder at the ensign, according to the sources.

The survey also showed that the captain had kicked other crew members and thrown notebooks at them.

The captain has acknowledged giving strict orders aboard the ship, according to sources.

The MSDF set up an investigative committee into the ensign’s death on Dec. 18 at the Fleet Escort Force’s headquarters in Kanagawa Prefecture.

In 2004, a 21-year-old MSDF seaman assigned to the Tachikaze destroyer killed himself after his supervisor punched and shot him with an air gun.

In 2014, a petty officer third class in his 30s committed suicide aboard a destroyer. He had been slapped by a superior officer, struck in the head with a pen light, and told to “quit the SDF” and “go back home.”

The superior also forced him to stand still holding buckets full of water.

To deal with the problem, the Defense Ministry in 2016 adopted such measures as setting up a telephone hotline at all branches of the SDF for victims of “power harassment.”

The SDF also provides consultation services for mental health issues and has a desk that allows whistle-blowers to communicate with outside lawyers.

But SDF members may find it difficult to contact the outside world because they work and live in close quarters with each other and perform long-term duties at sea.

The MSDF has about 42,000 members. In recent year, about 10 members committed suicide annually.

However, the MSDF generally does not disclose suicides for privacy reasons.