South Korean police have arrested seven railway employees on suspicion of negligence in last week's subway arson inferno that killed at least 133 people.
An investigator also said police planned to widen the investigation to include the manufacturer of the trains and the head of the subway system in Daegu, 120 miles south of Seoul.
Among those arrested was the driver of a train that stopped alongside that set ablaze by an apparent arsonist. The alleged arsonist has been identified by police as a 56-year-old former taxi driver with a history of mental problems, who was apparently suicidal but did not want to die alone.
The other six arrested employees were at the subway control centre, which allowed the second train into the central Taegu subway stop despite knowing there was a fire there, the investigator said.
Most of the deaths were believed to have been on the second train, which survivors said stood alongside the first with its doors shut for many minutes - some reports say as long as 20 minutes.
The investigator said the seven subway employees were arrested because of fears they might go into hiding and that formal charges would be filed against them later.
Some 128 people are in hospital and more than 300 people are missing.