“If a coal mine wants to keep two sets of books, that’s their own business,” Mr. Stricklin said. “What they have to do is record the hazards associated with the examination in the official record book, and that wasn’t the case here.”

Ted Pile, a spokesman for Alpha Natural Resources, the company that acquired Massey in a merger this month, said that company officials had heard the information for the first time on Wednesday “along with the rest of the public,” and that until the company completed its own investigation it would not be in a position to comment.

In a presentation in Beaver, W. Va., Mr. Stricklin offered a stinging indictment of Massey practices, saying the federal investigation by more than 100 people had been able to rule out the company’s assertion that the explosion on April 5, 2010, happened because of an event beyond its control: a huge inundation of gas.

His findings matched those of the earlier report, conducted by a former federal mine safety chief, Davitt McAteer, which said that coal dust had been allowed to accumulate, spreading what had been a small ignition of methane through the mine and creating the deadliest mine blast in 40 years. “We are further along than this just being our theory,” Mr. Stricklin said. “This is our conclusion.”

Image A candlelight vigil in April 2010 for miners killed at a West Virginia mine. Investigators say the company took systematic and premeditated steps to circumvent government inspections. Credit... Mark Wilson/Getty Images

It is not unusual for a mine to keep several sets of books to track things like production and safety examinations before and during shifts. But it is against the rules to note problems with safety only on internal books, which are not required to be shown to federal or state inspectors, and leave them off the official books, which are required.