Police said Wednesday they have arrested a 14-year-old Tokyo boy on suspicion of coercing his girlfriend into prostitution by assaulting her and threatening to leave her.

The second-year student at a public junior high school in central Tokyo allegedly forced his girlfriend, a third-year student at the same school, to have sex with a 39-year-old man for 30,000 yen on Aug. 30 in violation of the Child Welfare Law.

The man, whom the then-14-year-old girl met through a telephone club, is a public elementary school teacher in Chiba Prefecture, police said. Police will soon report his case to prosecutors as a suspected violation of a child welfare ordinance in Saitama Prefecture, where the meeting took place, they said.

The boy allegedly used physical violence and threatened to break up with the girl if she did not prostitute herself to repay his debts, they said. He is said to have admitted to the charges against him during police interrogation.

The boy and the girl started dating around June and she allegedly prostituted herself 10 times, including the August incident, between late June and September because she did not want to break up with him, according to police.

She gave all the money she earned from prostitution to the boy, police said. The boy told police that he used the money to pay back debts incurred in computer poker games and as bets in more games, according to police.