The Hokkaido police searched in a helicopter and ended up finding a giant SOS sign made of 19 birch trees, each roughly 5 meters long.

In a separate area near the SOS sign, the police discovered a hole just large enough to fit a single human, which included four cassette tapes, a tape recorder, a backpack, some amulets, a human skull, a tripod, a pair of men's basketball shoes, two cameras, a notebook, and the driver's license of Kenji Iwamura, a 25-year-old male office worker from Kōnan, Aichi Prefecture who had gone missing on 10 July 1984 after he set out hiking to Asahidake.

When Iwamura failed to appear for work a week later, his parents asked police to search for him, but they found no trace.

[citation needed] The human bones were sent to Asahikawa Medical University and were identified initially as those of a woman aged 20–40 years.

Lift me up from here!The rest of the tapes included music from the anime TV shows, Macross and Magical Princess Minky Momo.

On the other hand, since the human skeleton was initially identified as a female, it was thought by investigators that there were two men and a woman that had gone missing at the park.

The identity of the woman and the potential relationship to Iwamura was unknown and caused confusion in the investigation and media coverage.

[7][1][3][9] The Asahikawa East police station announced on 28 February 1990 that after a reexamination of all the human bones that were found, they now believed that the skeleton was actually male, not female.

Some have pointed out that Osamu Tezuka's Astro Boy has a scene in which fallen trees are arranged in the shape of SOS.