The NRA had no immediate comment, but a retired FBI agent told ABC it is easy for industry groups and companies to infiltrate citizen groups since they often rely heavily on volunteers and don't have the resources to check backgrounds.

ABC said Sunday it confirmed the hired infiltrator, one Mary McFate, had been a member of three gun-control organizations, and had even run twice for the board of the nationally known Brady Campaign to Prevent Gun Violence

"This reinforces what we have long known, that the gun lobby will go to any lengths, no matter how unethical, to protect the profits of the gun industry in this country," said Angus McQuilken, whose organization, Freedom States Alliance, kicked "McFate" off its board after her true identity was learned.

ABC said the magazine Mother Jones reported recently that McFate, whose real name was Mary Lou Sapone was a consultant for a now-defunct security firm hired by the NRA to keep an eye on groups seen as a threat to unfettered gun ownership.