An officer took a battery report from a female patron/victim at the Bay Fair station who was hit on the head with keys by a female suspect. The battery occurred on a train in downtown San Francisco approximately 20 minutes earlier. The victim stated the suspect off-boarded at the Montgomery station. Suspect desrcripton: BF, 40’s, pink shirt, jeans, tattoo on neck. Officers conducted a search for the suspect at the Montgomery station with negative results. The victim was not injured.