The bank robber nicknamed the " Plain Jane Bandit" struck for a seventh time Monday, attempting to rob a Bank of America in Downey, Calif.
The woman has been linked to a series of five bank robberies and two attempted bank robberies around Southern California since July 12.
In all seven instances, the woman followed the same method, using both written and verbal demands and telling the bank teller an accomplice was waiting outside, said FBI spokeswoman Laura Eimiller.
Authorities have not disclosed how much money she has stolen. They have not suggested a possible name.
Witnesses describe the suspect as an Hispanic woman in her mid-30s, between 5-foot-3 and 5-foot-5 and 150-170 pounds. She may drive a silver four-door vehicle. Her alleged accomplice has not yet been seen.
Her nickname came from a witness' description of her as a "plain Jane."
U.S. Bank, where five branches have been hit, is offering a $10,000 reward for information leading to her arrest and conviction.
Anyone with information about the suspect's identity is urged to call the nearest FBI office or 911.