A 36-year-old San Francisco man has pleaded not guilty to charges of sex crimes against a 16-year-old autistic girl. The victim lived at a group home located in the Oakland area and wandered away from the facility in late November. The 16-year-old girl, who has the mental capacity of a much younger child, was initially followed for a time by some of the facility staff, but they lost visual contact with her close to the Fruitvale BART metro stop and called the police. From there, the girl was abducted and moved to a residence in the area. She was raped several times over three days. After she escaped, a train operator discovered her and alerted the police. She was able to help police find the man who allegedly attacked her.