Chicago police charged a woman they said attacked a man and a woman while on a CTA bus on the city's West Side on Sunday afternoon.

Diamond Miller, 37, of Chicago, was arrested and charged with four counts of aggravated battery.

Police said she was identified as the suspect who allegedly attacked a 54-year-old woman with a sharp object and beat a 35-year-old man on the bus in the 4000 block of West Cermak Road just before 1 p.m. on Sunday. She was taken into custody 20 minutes after the assault.

Police did not say what led to the attack. 

She is scheduled to appear at a detention hearing on Wednesday.

No further information was immediately available.