A mentally ill woman hacked her cousin to death at Annai Sivagami Nagar, Ennore on Sunday afternoon.

She then dragged the body out of the house and locked herself in.

Sources with the Ennore police identified the victim as Bir Fathima (50) of Gummidipoondi. She had come to Ennore to attend the marriage of Jamila Banu, the daughter of her cousin Fathima Beevi (43).

On Sunday morning, the family members went to a hall in Annai Sivagami Nagar 5{+t}{+h}Street, Ennore for the wedding. Fathima Beevi, who has a history of mental illness, abruptly began screaming and shouting at the wedding hall. Her relatives immediately sent her back to her house in Anna Sivagami Nagar 1{+s}{+t}Street accompanied by Bir Fathima.

“Once in the house, Fathima Beevi suddenly stabbed Bir Fathima with a kitchen knife on the back of her head killing her on the spot. She then dragged the body and left it outside the house. Neighbours who spotted the body alerted the police,” said S. Lakshmi, Deputy Commissioner of Police, Madhavaram.

Ennore police reached the spot, recovered the body and arrested Fathima Beevi who had remained in the house. She told police she had heard voices commanding her to kill her cousin.

Fathima Beevi underwent an abortion after her marriage leading to mentally instability. She had been undergoing treatment for the last two decades including sessions at the Institute of Mental Health in Kilpauk. She had attempted suicide on three occasions, police sources added.