A manga platform run by the major Japanese publisher Shogakukan Inc allowed an author to produce works under a different name despite knowing he was convicted of a sex crime, according to people familiar with the case and a recent court ruling.

An editor of the Manga One platform also got involved in out-of-court settlement talks between the author and the victim at one point, and proposed notarizing the terms being negotiated, they said.

Shogakukan has removed from the platform the manga series published under the new pseudonym and stopped shipping related books following an uproar over the handling of the situation.

"We should not have used the author," Manga One said Friday, calling its editor's involvement in the settlement talks "inappropriate." It also issued an apology to the victim and others affected.

Details of the case emerged from a Sapporo District Court ruling over a damages suit that ordered the author to pay 11 million yen in compensation.

The Feb 20 ruling noted that the plaintiff was diagnosed with post-traumatic stress disorder after the author sexually abused her for a prolonged period of time. She had been one of his students at a distance-learning high school in Sapporo when the sexual abuse occurred.

According to the ruling, a summary court had convicted the author in February 2020 of producing sexually abusive material that involved her, and ordered him to pay a 300,000 yen penalty.

After the summary decision, Manga One suspended his title. In May 2021, one of its editors joined a chat group in which the author and the victim were discussing the terms of a potential settlement.

The editor proposed notarizing draft terms that included a 1.5 million yen payment to the victim and required her to keep the sexual abuse against her secret. The two sides eventually failed to reach a settlement.

In 2022, a new title by the same author was launched on the Manga One platform, but under a different pen name.

"While we don't know how much the editor and Shogakukan knew of the seriousness of his crime, they should be held socially responsible," said the victim's attorney, Hiroko Kotake.

Shogakukan said through its press office that it will look into the case and take "necessary measures."