US lawmakers are probing Credit Suisse Group’s compliance with sanctions related to Russia’s invasion of Ukraine and have asked the Swiss bank to provide all relevant documentation.

Credit Suisse was asked to hand over documents related to the financing of yachts and private jets owned by potentially sanctioned individuals, according to a letter sent by the US House of Representatives’ Committee on Oversight and Reform to the bank’s chief executive, Thomas Gottstein, on Monday.

The probe comes after the Financial Times reported earlier this month that Credit Suisse had asked hedge funds and other investors to destroy documents relating to its richest clients’ yachts and private jets, in an attempt to stop information leaking about loans to oligarchs who were later sanctioned.

The letter was sent by US representatives Carolyn Maloney and Stephen Lynch. Maloney chairs the House Oversight and Reform Committee and Lynch is chairman of the Subcommittee on National Security. The letter expressed concern over the timing of the bank’s instruction to destroy the documents as it coincided with Switzerland’s statement that it would join other countries in imposing sanctions on Russia.

Credit Suisse on Monday declined to comment on the probe. It referred back to a statement made earlier this month in response to the FT’s report.

In that statement, it said that the request had been made to ensure investors complied with a nondisclosure agreement and was “in no way linked to the recent implementation of additional sanctions – with which we are fully compliant.”

Credit Suisse has been asked to comply with the committee’s request by April 11 and will need to send documents starting from January 2017 to present day, according to the letter.

The probe is another headache for Gottstein as he looks to get the bank back on track following a challenging 2021. Last year, the bank’s chairman, Antonio Horta-Osorio, resigned after an internal investigation revealed he breached COVID-19 rules, lost billions of dollars from the collapse of investment fund Archegos Capital Management and was tarnished by its involvement with now-defunct financier Greensill Capital.

Credit Suisse stopped pursuing new business in Russia after the invasion of Ukraine on Feb. 24, the Swiss bank said on Monday in an internal document seen by Reuters. 

Prominent US lawmaker Maxine Waters last week asked more than 30 financial services trade groups for information on what steps their members have taken to end business relationships in Russia.