Sensors pointed to high levels of toxic gas inside a coal mine days before Turkey's worst mining disaster, but company officials took no action, reports in the country claim.
Prosecutors formally arrested two more people today over the fire in the mine in the western town of Soma that killed 301, raising the number of suspects facing charges of negligent death to five.
Hurriyet and other newspapers report that data seized by prosecutors indicate sensors showed high gas levels inside the mine two days before the disaster.
They did not cite a source for the report, but miners interviewed by the Associated Press also alleged that supervisors ignored rising gas levels and failed to take precautionary measures.
Most victims died from toxic gases released by the fire.