Ladonna Christian, 46, of San Francisco was arrested Thursday night in the Mission, Shyy said.
Park and Mission station investigators “worked tirelessly” to identify and arrest Christian as the suspect in the robbery, Shyy said.
About 1:45 p.m. Monday, the 8-year-old girl and some friends had been selling candy in the area in front of a convenience store at Divisadero and Eddy streets.
When her friends were inside, a woman approached the 8-year-old girl, who was holding the bag of money from the sales of the candy.
The woman asked the girl to make change for the bus. As the girl went to make change, the woman twisted the girl’s arm, making her drop the money.
The woman then took the money and fled on a Muni bus. Police have identified Christian as that woman.
Christian was booked on charges of robbery, felony assault and willful cruelty to a child, Shyy said.