FILE PHOTO: Switzerland's national flags fly beside the logo of Swiss bank Credit Suisse in Zurich, Switzerland April 24, 2017. REUTERS/Arnd Wiegmann/File Photo

ZURICH (Reuters) - Geneva prosecutors said on Tuesday they are looking at whether Credit Suisse CSGN.S exercised adequate oversight of money deposited in its accounts that belonged to Turkish investors who suffered losses.

Two independent asset managers who used Credit Suisse accounts to deposit money from wealthy Turkish clients are suspected of covering up losses linked to the Turkish lira’s collapse in 2013.

Prosecutors recently began investigating whether Credit Suisse should have done more to halt transactions that led to losses, the Tages-Anzeiger newspaper reported.

Geneva prosecutors confirmed they had expanded an existing criminal investigation to include four people employed by Credit Suisse SA at the time.

“They have been heard as defendants of complicity in fraud and money laundering, with this part of the procedure still in progress,” the prosecutors said in a statement.

“The public prosecutor also confirms that Credit Suisse SA has become a money-laundering defendant,” the prosecutors’ statement said.

In a statement the Swiss bank said: “Credit Suisse firmly rejects any criminal liability and will vigorously defend itself against the allegations with all available means.”

($1 = 1.0114 Swiss francs)