A body found on a mountain in Hitoyoshi, Kumamoto Prefecture, may be that of a high school student missing since early May, police said, reporting that autopsy results showed it was that of a woman in her late teens or 20s.

The Kumamoto Prefectural Police have set up a team to look into the case, suspecting it is that of Mayuko Arakawa, 17, who was reportedly killed and whose body was abandoned in the mountains, they said Sunday.

The body was found Saturday near the top of Mount Takatsuka after a 47-year-old unemployed man confessed to killing Arakawa and dumping her body.

The man, Wataru Akaishi of Hamamatsu, Shizuoka Prefecture, had been arrested for alleged sexual assault on another woman.

During interrogation, Akaishi reportedly admitted to his involvement with Arakawa, a third-year student, who went missing May 4.

Police said the body was likely dead for two weeks to two months before it was found. They will conduct a DNA analysis to identify the body and determine the cause of death.

Investigative sources said Akaishi and Arakawa spent several hours together on the morning of May 4, the day she vanished. Akaishi, who stayed at a hotel in Hitoyoshi from May 2 to 4, returned his rented car around noon on May 4.

Akaishi became acquainted with Arakawa via an online dating site, they said. It is possible they met when Akaishi visited Hitoyoshi on April 2.