Police wrapped up their investigation Monday into the case of a 15-year-old boy in Nagoya who was extorted out of 54 million yen by his classmates while he was a student at a local junior high school.

Aichi Prefectural Police sent to prosecutors investigation papers on three more youths involved in the extortion. Two of them were boys who were in the same grade as the victim at the junior high school, while the other was a 14-year-old girl, police officials said.

A total of 10 boys arrested in the case have been turned over to the Nagoya Family Court. Prosecutors have suggested that three of the suspects should be sent back to them and tried in a criminal court.

Investigations so far have found that the suspects extorted money from the victim on 130 occasions since last summer, police said.

About 15 million yen of the amount went to a 16-year-old boy believed to be the leading figure in the extortion ring, police said. He had gone to the same junior high school as the victim.

The suspects are believed to have used the money to cover their pachinko, video game and other entertainment expenses. They also used taxis, bought jewelry and made trips to Tokyo and Nagano, the officials said.

One of the suspects also bought a motorcycle with the extorted money.