Credit Suisse Group AG asked a Swiss prosecutor to seal a report by the Swiss Financial Markets Authority into the bank's failure to detect and avoid fraud at its wealth management arm, Bloomberg News reported.

Prosecutor Yves Bertossa is required by Swiss law to seal the report following a request, in line with a legislation that is meant to prevent self-incrimination during a criminal investigation, blocking prosecutors from examining or using evidence under seal, according to the Dec. 5 report.

Bertossa has now asked a court to lift the order on FINMA's report, which prosecutors need access to as part of a probe into alleged forgery in a case involving former Credit Suisse wealth manager Patrice Lescaudron, the news agency reported, citing a spokesman for the prosecutor's office.

The original case did not cover allegations of forgery on Lescaudron, Bloomberg noted.

In early 2018, Lescaudron was sentenced to five years in jail after a Geneva court found him guilty of hatching up a scheme involving the transfer of cash from client accounts to cover up millions in trading losses. However, he was released later that year following a request to an appeals court.

A group of the bank's clients, who have previously filed lawsuits on the matter, claim that Credit Suisse is not disclosing all the details it knows regarding the matter. Credit Suisse maintains it had no knowledge of Lescaudron's deception.

Geneva prosecutors have been ordered by Switzerland's highest court in February 2019 to revisit claims from one of the fraud victims about Lescaudron's past behavior. They are now seeking to access details of FINMA's report that the bank demanded to be sealed, people familiar with a correspondence related to the request told the news agency.