Deutsche Bank was already under federal investigation for helping wealthy Russians launder money when it struck a deal last year to sell a property it co-owned in California.

The $72 million sale of an office complex might not have been notable, except for one thing: The purchaser was linked to the son of a former top Kremlin official.

The German bank was facing multiple money laundering investigations as well as political scrutiny over its ties to President Trump. Against that backdrop, bank executives in the United States raised objections about the proposed transaction, warning that while not illegal, it could further damage the bank’s reputation. Executives in the bank’s Frankfurt headquarters decided to go forward with it anyway.

After the sale went through, Deutsche Bank officials in the United States took the rare step of contacting the federal watchdog that polices financial crimes to report the bank’s own transaction as suspicious, according to three people briefed on the matter who were not authorized to speak publicly.