San Francisco police said the 70-year-old woman was beaten and robbed on July 31 in the 100 block of Francisco Street.
The victim told police she was standing in front of a building when she was approached by four young people who started talking to her.
Police said there was a language barrier between the woman and the suspects, so she couldn't understand what they were saying.
The woman turned to enter the lobby of the building when the four followed her inside.
Police said while inside the building, the suspects beat and robbed the woman of her property.
The woman was taken to a local hospital and treated for non-life-threatening injuries.
At a press conference on Monday, San Francisco police identified the suspects as 18-year-old Darryl Moore, of Oakland, and an 11, 13, and 14-year-old.
Moore, along with the 11 and 13-year-old, were arrested Wednesday in Milpitas in connection with an unrelated crime. Details of that crime were not made public.
The 14-year-old has not been located, and a warrant was issued for their arrest.
The 11-year-old won't be charged in the case because of their age, Scott said.
San Francisco police Chief Bill Scott called the arrests "really, really sad," given their age.
District Attorney Brooke Jenkins also spoke out at the press conference and said, "I think a greater dialogue and discussion has to begin when we are seeing our children involved in these types of crimes. I think it sends a message to us all that we need to do more as a community in San Francisco, more broadly, to discuss how we got to this point."