The city police have arrested two persons for alleged sexual assault of a 28-year-old mentally ill woman near Brooke Bond Road on Saturday night.

The police said M. Arjunan (27) of Ramnagar is a scrap iron trader and saw a woman standing before his shop at Ganapathy.

Arjunan took the woman on his motorcycle and committed the crime in a bush on Brooke Bond Road close to the railway line.

Later rag picker A. Pandiyan (22) of Arupukottai also committed the crime.

On hearing the loud cries of the woman, a passer-by informed the police control room and the two were arrested. The police have registered a case.

City Police Commissioner Amaresh Pujari said that a timely call by the passer by and the instant reaction by the emergency response system at the control room ensured that the police were there within three minutes, leading to the arrest of the accused.

Otherwise the case would have remained an unresolved mystery as the victim was mentally-ill.