A U.S. Navy soldier was found dead near a Japanese train station. The first investigations indicate that the soldier suffered a severe head injury, but police will continue to investigate his mysterious death for more information, Fox News relates.

A U.S. Navy soldier, identified as Petty Officer 2nd Class Samuel Lewis Stiles, was found dead near a Japanese train station on early Tuesday morning. The man was lying breathlessly on the platform in Haiki Station in Nagasaki Prefecture when police officers discovered him. He was surrounded by eight empty cans of alcoholic drinks and had suffered a severe injury to the head. It is believed that the head injury might have led to the man’s death, but medical analyses will shed more light on the case.

Given the lack of sufficient evidence, authorities think the case could turn out to be either an incident or a murder. The death comes at a difficult moment for the U.S. military in Japan because two sailors were arrested two months ago after they were found guilty of raping a Japanese woman. In response, the U.S. military imposed a curfew on its troops prohibiting soldiers to leave their bases, personal homes or hotels between 11 p.m. and 5 a.m. The lifeless body of the man was found around 5 a.m. which is a clear indicator that the sailor breached the curfew.

Stiles was dressed in civilian clothes, instead of uniform, when police officers found him on the Japanese train station. Authorities looked for his personal belongings, but they didn’t manage to find anything, so investigators do not exclude the possibility that the soldier was robbed. Samuel Lewis Stiles was stationed at the U.S. base in Sasebo, a city in Nagasaki where Haiki Station is situated.