SUNDERLAND - Police were last night hunting four youths after a nine year old boy was hit by a petrol bomb and became engulfed in flames. Shaun Hackett's jacket caught fire after the bomb was thrown while he and his 11 year old friend looked for conkers in the Loft Hill area of Doxford Park Estate, Sunderland. He was treated for burns at Sunderland General Hospital. Det Insp Jim Cameron said Shaun's friend, named only as David, told them the bomb was thrown by one of four youths, aged 13-15, who approached them.