The Justice Ministry on Friday effectively demoted Eiju Yamashita, 51, the deputy head of the Fukuoka District Public Prosecutor's Office, for his alleged involvement in leaking police information to a judge about an investigation of the judge's wife.

Effective Friday, Yamashita was transferred to the general affairs department of the Fukuoka High Public Prosecutor's Office, and his new post has not yet decided.

His replacement will be picked from the high prosecutor's office.

A director in charge of the ministry's personnel division insisted that the personnel reshuffle is not meant as punishment.

"It has become difficult (for Yamashita) to carry out his duties as the deputy head of the prosecutor's office" because the Supreme Public Prosecutor's Office is questioning Yamashita about his involvement in the case," the official said.

The official went on to stress the need to quickly fill Yamashita's post, which he calls a "keystone" in the prosecutor's office.

Earlier Friday, Justice Minister Masahiko Komura said the ministry will dispatch an investigator from the Supreme Public Prosecutor's Office to further look into the allegation that a prosecutor leaked information to a judge.

"It is necessary to investigate the allegations thoroughly to cope with criticism that legal professionals help each other (in cases like this)," Komura told reporters.

Komura made the remark as police investigated allegations that Yamashita leaked to Judge Ryuichi Furukawa, 48, investigative information on the judge's wife, Sonoko.

Sonoko Furukawa was arrested on suspicion of threatening to kill another woman.

The wife was arrested on suspicion of sending 10 e-mail messages between Dec. 14 and 21 to a woman, saying, "I will kill you" and "Beware when you walk at night."