According to authorities, the unidentified woman is responsible for at least three thefts in the Santa Clarita Valley area Saturday.
Police say the suspect targeted women shopping at grocery stores, swiping their wallets from their purses.
"Shortly after the wallets were stolen, the victims reported that their credit cards and ID's had been used for various purchases," Los Angeles County Sheriff's Department Deputy Joshua Dubin said.
The suspect chose victims with similar looks. She was captured in surveillance photos at several locations where she made purchases and obtained cash while posing as the victims.
"We started receiving reports from various jewelry stores, various banks, that these credits were being used," Deputy Dubin said. "The female suspect entered these locations posing as the various victims."
Investigators say she tried to purchase $20,000 worth of merchandise at a mall jewelry store. When the store hesitated to put the purchase on a credit card, she fled.
The suspect was seen driving a silver Cadillac SUV with paper license plates and was accompanied by a male passenger, who authorities say may be an accomplice.
The person seen in the passenger seat of the suspect's car was described as male black adult.
Shoppers are being warned to keep an eye on their belongings.
Sharon LaPointe said she makes sure to stay vigilant while shopping in case unscrupulous people are tempted to steal.
"I don't ever turn my back and just walk off, LaPointe said. "I'm always aware."
The female suspect's vehicle was also seen at a Santa Clarita Valley area gas station last Saturday. The woman and her suspected accomplice purchased gas for their vehicle and a third party, seen driving a black four-door vehicle.
Investigators believe this lookalike thief and her accomplices have committed similar crimes in other parts of Southern California.
Anyone with information regarding the suspects or thefts was urged to contact Detective Jones at (661) 255-1121.