At about 1:10 p.m. last Wednesday, police received a report of a woman who brandished a knife at a store in El Cerrito, police said.
Police Cpl. Gilbert Tang said that when the woman attempted to leave the store without paying for some merchandise she had taken, employees there tried to restrain her.
That prompted the suspect to brandish a knife, which she waved threateningly at store employees before fleeing the store while pushing a stroller with a baby inside, police said.
Officers located the woman, 29-year-old Booshondia Daniel, at the nearby El Cerrito Plaza BART station, Tang said.
Daniel was identified as the suspect in the armed theft and was arrested and booked into jail in Martinez, police said.
During a search, police found her to be in possession of a burglary tool and a glass pipe, according to police.
She has since been charged with second-degree robbery and an enhancement for use of a deadly weapon, a Contra Costa County District Attorney's Office spokeswoman said.
The infant's father took custody of the baby at the El Cerrito Police Department.