A man was fighting for his life last night after a fire was started by a petrol bomb thrown into an Aberdeen flat. Widower Yau Kar-yu, 41, who lives alone in the apartment in Wah Tai House, Wah Fu Estate, was found lying unconscious on the verandah with 70 per cent burns. He was taken to Queen Mary Hospital and was in a critical condition in the intensive care unit. Mr Yau was believed to have been taking a bath at about 7pm when a bottle of thinner with a cloth fuse was hurled into his sitting room, setting the flat ablaze. Neighbours saw smoke billowing from the flat and called police. The neighbours then helped firemen fight the blaze. The flat was severely damaged. Firefighters found Mr Yau in his underwear on the verandah. Fire officers investigating the blaze handed over the probe to police when they found the bottle containing traces of thinner in the gutted living room. Police said that they were investigating reports from some residents who claimed that they had seen several men go to Mr Yau's flat recently demanding that he make repayments for a loan. Mr Yau's 20-year-old son was said to live with his grandparents in another flat on the same estate.