NPR is standing by their initial report that Massey Energy is being investigated for possible bribery and criminal negligence. A federal source is denying the story:

A federal law-enforcement source is denying that the Mine Safety and Health Administration is being investigated as part of a larger probe into the circumstances surrounding the Upper Big Branch mine disaster in West Virginia.

NPR has reported that Massey Energy and MSHA were the subjects of investigations.

The federal law enforcement source said: "I can say that there's an investigation but it's not about them (MSHA)."

NPR stands by its earlier report.

The original post is below:

NPR News has learned that the Mine Safety and Health Administration is one subject of a federal criminal investigation surrounding the explosion of the Upper Big Branch mine in West Virginia three weeks ago -- a disaster that killed 29 miners. The probe also looks at Massey Energy, the owner of the mine.

Sources familiar with the investigation say the FBI is looking into possible bribery of employees of the Mine Safety and Health Administration, the federal agency that inspects and regulates mining. The sources say FBI agents are also exploring potential criminal negligence on the part of Massey Energy, the owner of the Upper Big Branch mine.

Massey has been cited repeatedly for violations of federal safety regulations and unsubstantiated rumors have circulated for years that mine inspectors and other officials receive payoffs. The FBI declines comment and neither confirms nor denies that an investigation is ongoing.

In a statement to NPR, Massey Energy says it is not aware of the allegations, and is fully cooperating with any investigations taking place. The Mine Safety and Health Administration has yet to respond to a request for comment.