The police on Sunday arrested a 34-year-old woman suspected of throttling her seven-year-old son to death at Atholi in Kozhikode. According to the police, the incident took place on Saturday. The woman had initially claimed that the boy died of cardiac issues. Police sources said the actual cause of death came to light following the post-mortem report. They also said a medical check-up would be conducted in the wake of some confidential reports that the woman was under treatment for mental illness.