(CNN) -- Federal prosecutors indicted an Arkansas doctor Wednesday in the bombing attack of the head of the state's medical board. It's the same board, prosecutors said, that had taken disciplinary action against the defendant.
Randeep Mann, a Russellville, Arkansas, doctor, is charged with one count of using a "weapon of mass destruction" against a person and property and a second count of "maliciously" using an explosive to damage or destroy a vehicle, according to prosecutors. Both charges accuse Mann of undertaking the crimes with the help of others, though the identities of others potentially involved have not been released.
The doctor who was the target of the attack survived but suffered injuries that included losing an eye.
A third charge filed Wednesday accuses Mann of possessing chloroform in his jail cell, according to a news release from the U.S. Attorney of the Eastern District of Arkansas. Mann, arrested initially on firearms charges, has been jailed since March 4. U.S. Attorney Jane Duke, speaking at a news conference, declined to comment on the suspected purpose of the chloroform.
Attorneys for Mann had no comment when contacted by CNN on Wednesday.
Mann, whose specialty was internal medicine and pain management, allegedly set off an explosion that injured family practitioner Trent Pierce on February 4, outside Pierce's West Memphis, Arkansas, home. On his way to his clinic that morning, the chair of the Arkansas State Medical Board went out to start his Lexus hybrid SUV. Before he ever got into the car, a bomb went off, Duke said.
The blast, heard a mile away, threw Pierce six feet into a flower bed, police said. Pierce lost his left eye in the explosion, and suffered burns to his face.
Pierce was due at a subcommittee meeting of the state medical board later on the day of the attack, Duke said.
Early in the investigation, cases before the medical board were examined for potential leads. The board oversees licensing of medical professionals, and, in some cases, disciplines those professionals by suspending or revoking their licenses.
Mann had "multiple disciplinary matters" before the board, Duke said.
A call by CNN to the board's counselor for information on cases against Mann was not immediately returned. But Duke said the board had taken several disciplinary actions against Mann's license.
Mann was interviewed by federal agents the day of the bombing and showed them "at least one grenade launcher he legally owned," the U.S. attorney's office said in the release. But he wasn't arrested until a month later, after city employees uncovered partially buried "high explosive rounds designed to be fired from a grenade launcher" in a wooded area of London, Arkansas, the release said.
An August indictment against Mann charged him with four counts involving the possession of unregistered firearms and explosives, including a machine gun and 98 grenades, according to court documents.