The investigation includes a review of reports that the bank’s employees prepared about possibly problematic transactions, including some linked to President Trump’s son-in-law and senior adviser, Jared Kushner.

Origins: Agents told one person interviewed that the investigation began with an inquiry into the bank’s work for Russian money launderers and had expanded to cover a broader array of potential misconduct at the bank and other financial institutions.

One element is the banks’ possible roles in a vast money-laundering scandal at the Danish lender Danske Bank.

How we know: We spoke to seven people familiar with the inquiry.

Reminder: A former compliance specialist at the bank told The Times last month that she had flagged transactions involving Mr. Kushner’s family company in 2016, but that bank managers decided not to file the so-called suspicious activity report she prepared.