The prosecution yesterday offered no evidence against a mother accused of drowning her six-week-old son. John Reading SC, deputy director of public prosecutions, told the Court of First Instance that the death happened after the hospital removed life-support equipment from the baby, who was in a coma for 18 days last year. That, he said, made it difficult to prove the direct cause of death. Housewife Law Lai-yu, 39, pleaded not guilty to infanticide of her first and only child, who died after allegedly being submerged in the bathtub at Ms Law's home in Western district. The baby boy was admitted to Queen Mary Hospital with severe brain damage and was on life-support equipment until it was removed on August 18 last year. The court was also told that the mother was under psychological treatment. Deputy High Court Judge Derek Pang Wai-cheong released Ms Law after the Department of Justice offered no evidence and decided not to proceed with the case. The hearing was initially set for five days. Outside court yesterday, Ms Law's defence counsel, Michael Delaney, said his client had been very distraught and depressed after losing her baby. 'It was a tragedy,' Mr Delaney said.