(Gary Denness / Flickr)

Citigroup has now fired a total of 12 employees tied to the alleged accounting fraud at its Mexican subsidiary, Banamex, news outlets including The New York Times reported Wednesday.

In addition to one low-level employee let go earlier this year, Citigroup revealed in an internal memo published by the Times that 11 other employees, including four managing directors, have now been fired.

Citigroup CEO Michael Corbat said in the memo that the bank had fired the employees “for not doing enough to protect the company from this fraud.” He also wrote: “Additionally, before our investigation concludes, we expect that several other employees, both inside and outside of Mexico, may receive forms of disciplinary action as well.”

The disclosure is the latest development in an ongoing inquiry into alleged loan fraud at Banamex. In February, Citi revealed that it had realized a loss of $235 million due to $400 million in bad loans made by its Mexican subsidiary to Oceanografia SA de CV, an oil-services company in the country.

Federal authorities, including the Federal Bureau of Investigation and the U.S. Securities and Exchange Commission, are also investigating the alleged fraud. Citigroup’s internal investigation is being led by frequent outside counsel Shearman & Sterling, as law.com previously reported.

Corbat stated in the memo that “we are sharing information with our regulators and law enforcement agencies, which will make any determinations as to criminal liability for the fraud.”