The Charleston Gazette reported Friday it had obtained a copy of a letter sent from the bureau's Charleston office informing the families that because of the criminal investigation they may be entitled to government services. The letter was signed by the agent supervising the office, Joseph I. Ciccarelli, and was dated March 28.
The explosion occurred April 5, 2010, at the Upper Big Branch mine, owned by Massey Energy. The letter said the FBI is involved in the investigation of potential violations of federal laws.
"In connection therewith, you may be a victim of a federal crime," the letter said. "We appreciate your assistance and cooperation while we are investigating this matter. We would like to make you aware of the victim services that may be available to you and to answer any questions you may have regarding the criminal justice process throughout the investigation."
The office of U.S. Attorney Booth Goodwin in Charleston, who declined to comment on the letter, has filed two criminal cases related to the mine, though neither is directly linked to the cause of the deadly explosion, the Gazette reported.
The newspaper said previously revealed documents indicated federal investigators also are looking into potential crimes related to hundreds of safety and health violations cited at the Massey mine dating to 2006.
The company also declined comment on the FBI letter, the Gazette said.
Notable deaths of 2014 [PHOTOS]