The Justice Ministry has concluded that prosecutors forced witnesses to commit perjury in a bribery case involving former Prime Minister Han Myeong-sook and that it reassigned the alleged perjury case to impede the investigation.

Justice Minister Park Beom-kye announced the findings on Wednesday, as part of an outcome of the ministry and prosecution's four-month inspection into questionable investigative practices.

As a preventive step, the ministry demanded prosecutors minimize meetings with witnesses and record the interviews they conduct with them. The ministry will also restrict the prosecution's case assignments and formation of investigation teams.

Last year, allegations surfaced that prosecutors had forced late businessman Han Man-ho's fellow inmates to give false testimony about the former prime minister during her trial in 2011 in order to win a conviction.

Prosecutors earlier dismissed the perjury charges. But in March this year, the justice minister exercised his command authority and ordered the Supreme Prosecutors' Office(SPO) to review the case for any "unreasonable decision-making."

Some one dozen high-ranking prosecutors, led by then-acting Prosecutor General Cho Nam-kwan, convened for a review, and later decided to dismiss the perjury charges.