Police are investigating whether negligence contributed to the high death toll in the devastating subway fire in Daegu. Police are also looking to see if attempts were made to cover up any wrongdoing in Tuesday's disaster. But the chief investigator cautioned it is too early to say whether charges would be filed against any subway officials. The role of the driver who stopped his train alongside one set ablaze by a suspected arsonist is a particular focus of the investigation. The driver of the second train told investigators that he ordered passengers over the loudspeakers to get out three times and waited ten minutes before removing the masterkey which controls the train and doors and leaving the train himself. Police said the suspected arsonist has a history of mental illness. The 56-year-old former taxi driver lit a container of flammable liquid in one car after the train arrived at a stop. He is in hospital with burns and too ill to be questioned. Police earlier quoted him as saying that he had planned to commit suicide, but then decided he did not want to die alone. The accident in the nation's third largest city some three hundred kilometers southeast of Seoul is the worst in years. At least one-hundred-33 people are dead with several hundred still unaccounted for.