Three badly burned safety hammers were found yesterday in the wreckage of a bus engulfed by a fire on Friday that killed at least 25 people and injured 76 in Sichuan . But Hu Qinghan, director of the Chengdu city's transport commission, said he would neither confirm where the hammers were found nor whether trapped passengers had tried to use them to break the bus windows. 'We cannot prove whether the passengers used the hammers or not. But they were on the bus at the time,' he said. Witnesses on Friday said there were no safety hammers because they saw trapped passengers banging their heads against the windows trying to break the glass. The fire erupted in a packed bus carrying 120 commuters from the outskirts of Chengdu to the downtown area at around 8am. Police released the names of 70 of the injured yesterday. The identities of another four people could not be confirmed, as two were in serious condition, and two were deaf mutes. Two of the injured passengers, with minor injuries, had been discharged. earlier. Shen Chuanyong, deputy head of Chengdu's health bureau, said six of the injured were in critical condition, while another 20 were in serious condition. The death toll is expected to rise. 'The six in critical condition had suffered burns to 95 per cent of their body. Their vital signs are very unstable,' Mr Shen said. Police officers have confirmed the identity of 10 of the dead after DNA tests. Most of the bodies were too disfigured to be identified visually. The China Youth Daily yesterday quoted one witness who escaped from the bus as saying that he saw a man spilling flammable liquid before the fire erupted, but Mr Hu said there was no evidence to support the claim. There was no evidence of a fuel leak or engine problem and no sign of a bomb attack. Police could not find evidence of sabotage, but did not rule it out. The bus driver, who had tried to help people escape, was cleared of any wrongdoing and released. Many of the 200 relatives waiting to hear news were angry that local officials had offered them little help.