A body found in a cardboard box on a roadside in Tochigi Prefecture was that of a 16-year-old girl from Saitama Prefecture who went missing nearly two years ago, police said Monday.

The family of Kana Shiratsu filed a request with the Saitama Prefectural Police to search for her in September 2012, investigators said.

Police on Thursday arrested Haruyuki Iwasaki, 45, unemployed and with no fixed address, on suspicion of abandoning the body near a prefectural road in the city of Sano.

The body was wrapped in a blanket inside the cardboard box.

Another suspect, Toru Kuribayashi, 30, is wanted on suspicion of aiding Iwasaki, the police said.

An autopsy was reportedly unable to determine the cause of Shiratsu's death.

According to investigators, Iwasaki voluntarily showed up at Shinjuku Police Station in Tokyo on the night of Aug. 5, telling them he "was asked to abandon the body for a monetary reward."

The police found a car in Koshigaya, Saitama Prefecture, that they believe was used to take Shiratsu's body to Tochigi.

Before she went missing, Shiratsu, who originally hailed from Kitamoto, Saitama Prefecture, was living in a "welfare facility," the police said without going into specifics. The search was taken nationwide after the Saitama police failed to find her in the prefecture.

A 16-year-old friend of Shiratsu's from junior high school said Monday she was "shocked at the news" and that Shiratsu "was just as pleasant as any other friend."

The friend said Shiratsu was an avid member of the junior high school soft tennis club but stopped participating when she was in her second year at the school.