Citigroup is reportedly facing a criminal investigation after revelations of a $400 million fraud involving its Mexican unit, Banamex. In February, Citigroup revealed at least one Banamex employee had processed false documents which helped a Mexican oil services firm defraud the company. According to The New York Times, the FBI and U.S. attorney’s office in Manhattan have opened a probe into whether Citigroup ignored warning signs. The bank is also facing a separate probe from federal prosecutors in Massachusetts over the possible laundering of drug money through a Citigroup account. Citigroup received two taxpayer bailouts, racking up more in federal aid during the financial crisis than any other bank.