According to Los Angeles County Sheriff's officials, the woman was stopping at the Valero gas station and convenience store at 500 East Avenue K on Friday afternoon when she saw a man wearing a bandana on his face walk in behind her.
The woman quickly exited the store and called 911.
After the suspect fled the scene, the woman followed him from a distance, all the while staying on the line with police.
The suspect eventually stopped at an apartment complex at the 43500 block of Kirkland Avenue.
Deputies captured the suspect, identified as 21-year-old Deon Fite, after a short foot pursuit.
Fite, a parolee, was taken into custody and booked for robbery and parole violation. He is being held on $100,000 bail.
Deputies were able to retrieve the stolen cash and a handgun from Fite.