Brokerage firm Merill Lynch is suing a unnamed individual for allegedly posing as one of its bank managers for sending derisive emails to some of its investment brokers.

The unnamed defendant, known only as John Doe and thought to live sometwhere in the US Midwest, allegedly sent racially denigrating emails from a Microsoft Hotmail account to several of Merrill Lynch’s black brokers as well as civil rights leader Al Sharpton from mid-September.

The company filed the suit late on Tuesday in a US district court in Manhattan, New York. The company has sued for trademark infringement and asked the court to stop the dissemination of the emails. It is also asking for unspecified damages.

The e-mails sent by defendant contain explicit racial remarks that are meant to be offensive to the African-American employees of Merrill Lynch, the company said in a statement yesterday.

According to reports, the emails were made to appear as though they had been sent by a Merrill Lynch administrative manager and included a signature and references the Merrill Lynch trademark.

Merrill Lynch is also seeking a court order to publicly name the John Doe by obtaining information about the email account.

Sharpton is also joining the action and said in a statement: It sends a signal to other bigots and copycats who would try to hide behind an e-mail address.