Oakland police spokeswoman Johnna Watson said officers received a report of the shooting just after noon Thursday and found the girl in a downtown apartment with a fatal gunshot wound. The victim was pronounced dead by emergency medical workers.
Family members tell KTVU-TV that the girl was shot after getting into an argument with her brother over laundry. They say she had bleached some of his clothing.
Police have not confirmed a motive.
The investigation is ongoing.
Information from: KTVU-TV.