A woman never stopped talking on her cellphone as she robbed four banks in the Washington D.C. suburbs, a sheriff's spokesman says on Friday.

In the most recent heist, the woman walked up to a bank teller in Ashburn, Virginia on November 4 and opened her purse to show a handgun and a note demanding cash, says Loudoun County sheriff's spokesman Kraig Troxell.

"During the entire sequence, she was on her cell phone," Troxell says by telephone. "When we compared it with other robberies that have occurred in the area, we determined she was involved in three other robberies. ... In those cases, she was also on the cell phone."

No one was injured in the robberies, and the amount taken was not disclosed. Troxell says it is unclear what role the cell phone may have played in the case.

"With the use of the cell phone, was she just trying to act nonchalant, not drawing any attention to herself? Was there anyone even on the other line? Was there an accomplice? Was she just talking to someone on the phone who may not have been aware of what she was doing, just to help her through the crime?"

Troxell says there might have been an accomplice waiting outside, or "it could be ... she was just doing it to make herself look like anybody else."