Why did the Japanese civil servant sail to his death from South Korea in an inflatable dinghy?

Mystery surrounds the motives of a Japanese bureaucrat found dead after apparently attempting to sail approximately 50 kilometres from South Korea to Japan last month in a small inflatable dinghy.

The man has not been named by the Japanese government on the grounds of privacy. All that is publicly known about the victim is that he was a 30-year-old employee of the Cabinet Office in Tokyo who had been studying at a graduate school in the United States since last summer.

A spokesman for the Cabinet Office said it was investigating the case, which he agreed was "curious", but declined to identify the victim.

The bureaucrat had been granted permission by the ministry to attend an economic conference in Seoul in January.

The Cabinet Office said it had heard nothing from its employee after he arrived in Seoul.

On January 18 the crew of a pleasure boat off the city of Kitakyushu reported to the Coast Guard that they had spotted an apparently unconscious man in a rubber dinghy drifting near the outer breakwater.