A woman thought to be suffering from post-natal depression was arrested for suspected arson after setting alight magazines in front of her daughter and two-year-old son, police said. Her eight-year-old daughter called her father, 58, at work when she found her mother, 30, talking to herself then starting the fire in the kitchen of their flat in Tin Yiu Estate, Tin Shui Wai on Thursday evening. Firemen doused the flames. The mother was being detained in the hospital.