Two young sisters were found dead alongside their ex-policeman father in a fume-filled car yesterday. Wong Tak-lun, 30, was found in the driver's seat, cradling the body of three-year-old Wai-lok. His youngest daughter, two-year-old Wai-chi, was in the seat next to him. A plastic tube connected to the exhaust pipe had been fed through the driver's window of the car parked in Bride's Pool Road, Luk Keng. Wong's eldest daughter, aged five, was with his estranged wife, 29. Two months ago, Wong threatened to jump from a building in Aberdeen, but was talked out of it in a six-hour standoff with police. Yesterday's tragedy came to light when a passer-by noticed the white Nissan, parked in a lay-by near a barbecue area, about 10.30am and called police. The engine was running when officers arrived. Sha Tau Kok Divisional Commander David White said the three had been dead for two or three hours. The girls' birth certificates and father's home return permit were in the car, which Wong had borrowed from a neighbour. Detectives said Wong might have drugged the girls before gassing them. Police gathered at least three boxes containing food, drink and other items from Wong's home in Tung Che Road, Tai Po. A suicide note was found in the house which said he had no reason to live but did not give a specific cause for his suicide. Police said Wong had left the force six years ago, setting up his own interior design business. When the business, which ran quite well for a time, began to fail, Wong and his wife, 29, were beset by marital problems. Wong's wife had been staying with her parents in their home in Wah Fu Estate, Aberdeen since early this year. On Sunday, his wife visited the Tai Po home and took the three children away with her. But the next day, Wong collected the two youngest from Wah Fu, telling his Tai Po neighbours he would return them that evening. That was the last time he was seen. He had attempted suicide on July 3 after he was refused entry to his parents-in-law's home, holding officers at bay for about six hours before he was pulled away from the roof and taken to hospital for observation.