An alleged member of an ATM skimming operation plead guilty to one of several charges in federal court Monday.

Gabriella Graham, 21, of New London, plead guilty to one count of conspiracy to commit bank fraud, according to a press release from David B. Fein, United States Attorney for the District of Connecticut. According to the report, Graham helped produce counterfeit ATM cards, wrote pin numbers of the backs of the cards and, on occasion, used the cards to make unauthorized withdrawals from ATMs. Police also said she served as a lookout while other members of the conspiracy installed and removed the skimming devices, and made unauthorized withdrawals from accounts.

As a result, more than 250 bank accounts were victimized, and financial institutions have suffered losses of approximately $336,057.64.

Graham is scheduled to appear in court for sentencing March 8, 2012.

Graham faces up to 30 years in prison and a fine of up to $1 million.

Mehmet Aydin, 42, of Miller Place, N.Y., Ahmet Cilak, 40, of Levittown, N.Y., and Graham were each charged with one count of conspiracy to commit bank fraud, six counts of bank fraud and six counts of identity theft by a grand jury, according to a press release from U.S. Department of Justice.

The Darien Police Department arrested Cilak after receiving reports of a skimming device being placed on an ATM at Bank of America.

At approximately 8:45 p.m. June 24, police responded to the Bank of America at 7 Sedgwick Ave. Bank personnel claimed an ATM skimming device was placed on the ATM. A skimming device is an electronic reader used to illegally capture credit card and ATM card information as well as PIN numbers associated with the card.

Members of the Darien Police Department and members of the Connecticut Financial Crimes Unit conducted a surveillance of the bank and subsequently observed a white male wearing a camouflage shirt acting suspiciously in the area. The man, Cilak, was detained in the area of Old King's Highway North and Brookside Road.

The charges of conspiracy to commit bank fraud and bank fraud carry a maximum term of imprisonment of 30 years and a fine of up to $1 million, on each count. The charge of aggravated identity theft carries a mandatory term of imprisonment of two years, which must be imposed consecutively to a sentence imposed on any other count of conviction, the press release said.

Cilak and Aydin plead not guilty to the charges.