A letter from Credit Suisse sent to investors earlier this month allegedly asking them to shred asset-backed loan documents, is having further repercussions.

Senior members of U.S. Congress have reached out to Credit Suisse CEO Thomas Gottstein, asking him to hand over information on how the bank handled documents relating to loans on assets belonging to sanctioned Russians, the «Wall Street Journal» (behind paywall) reported Monday.

According to previous media reports, Credit Suisse sent letters to investors and hedge funds instructing them to destroy and permanently delete information provided by the bank on securitized loans backed by assets such as jets and yachts.

The U.S. Congress is concerned the bank might not be complying with sanctions imposed by the U.S. and its allies against Russia and has launched a probe into the matter, the newspaper says.

Credit Suisse sent the letters shortly after Switzerland said it would match sanctions imposed by U.S., U.K and the EU on Russia following its invasion of Ukraine, the report says.

Separately, Credit Suisse said on Monday it is no longer seeking new business in Russia.