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A gunman entered the headquarters of the conservative group Family Research Council in Washington, D.C., and opened fire on a security guard this morning, police said.

According to a spokesman for the DC Metropolitan Police Department, a suspect is in custody. The security guard was shot in the left arm and is being treated at a local hospital.

The Family Research Council is a conservative Christian group founded by James Dobson that lobbies and supports "traditional family values" according to its website.

DC Metropolitan Police are investigating the shooting along with FBI agents from the FBI's the National Capitol Response Squad.

Guards wrestled the gunman to the ground after the shooting in the lobby of the FRC HQ. The suspect was not shot.

The Bureau of Alcohol Tobacco, Firearms and Explosives is on scene also helping with the investigation to trace information about the firearm which investigators recovered from the scene.

Additional details are unclear in terms of motive or suspect's identity. ABC News affiliate WJLA reported that the suspect was taken from the building in handcuffs by police.

"The police are investigating this incident. Our first concern is with our colleague who was shot today. Our concern is for him and his family," said Family Research Council President Tony Perkins.

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