BART Officers responded to Union City Station concerning a battery in progress in front of the station. As the officers entered the station, they saw an adult female (BF, 19yo) striking an adult male (BM, 25yo). The officers detained the man and woman and determined the female had battered her boyfriend repeatedly when he was late picking her up. The victim had some cuts on his hand and refused medical or an emergency protective order. The suspect was booked at Santa Rita Jail for battery on a co-habitant. 1202-4158 L21.