Police said the man, identified as Floyd Lee Corkins II, entered the front lobby of the Family Research Council in downtown Washington around 10:45 a.m. Wednesday, began arguing with a security guard and then shot him in the arm. Corkins, 28, was taken down by the wounded guard and others and was being held Wednesday night on a charge of assault with a deadly weapon, the FBI said.
Authorities were interviewing Corkins to determine a reason for the shooting and were canvassing his neighborhood in Herndon, Va., outside Washington. TV news footage showed the suspect, a large man with a shaved head in an unbuttoned striped shirt, being led to a car in hand restraints.
Though authorities did not publicly reveal a motive, advocacy groups across the ideological spectrum condemned the violence, with some casting it as a hate crime. President Barack Obama was concerned about the wellbeing of the guard, a White House spokesman said, and Republican presidential candidate Mitt Romney also said he was appalled.
"Today's attack is the clearest sign we've seen that labeling pro-marriage groups as 'hateful' must end," Brian Brown, the president of the National Organization for Marriage, said in a statement.
The Family Research Council, headquartered in a busy downtown tourist district, strongly opposes gay marriage and abortion and says it advocates "faith, family and freedom in public policy and public opinion." The conservative group maintains a powerful lobbying presence on those causes, testifying before Congress and reviewing legislation. Its president, Tony Perkins, said the group's main concern was with the wounded guard.
Corkins who had been volunteering recently at a community center for lesbian, gay, bisexual and transgender people, made a negative comment about the organization's activity before the shooting, but the reference was not specific, one of the law enforcement officials said. Two law enforcement officials said Corkins was carrying sandwiches from Chick-fil-A, a fast-food chain whose president's opposition to same sex marriage recently placed the restaurant at the center of a national cultural debate.
James McJunkin, assistant director in charge of the FBI's Washington field office, said soon after the shooting that authorities didn't yet know enough about the gunman and his state to mind to know what inspired the attack.
The guard, Leo Johnson, was conscious and breathing after the shooting and was being interviewed and treated at a hospital. Authorities credited him for thwarting a shooting they said could have been much worse.
"The security guard here is a hero, as far as I'm concerned," said D.C. Police Chief Cathy Lanier.
Corkins had been volunteering for about the past six months at The DC Center for the LGBT Community, said David Mariner, executive director of the community center, which is in Northwest Washington. He usually staffed the center's front desk on Saturdays, and his most recent shift was about two weeks ago.
"He always struck me as a kind, gentle and unassuming young man. I'm very surprised that he could be involved in something like this," Mariner said.
Authorities seized Corkins' car at a northern Virginia Metro station, and were going door-to-door speaking with neighbors, several of whom spoke highly of the family.
"They were always so sweet and so nice," said Stephanie Meyer, who lives a few doors down. "They are awesome people. We never had any issues."
According to a U.S. Defense Department official, Corkins is not a member of the Air Force, but he may have lived at Andrews Air Force base in some other capacity in the past, possibly as a dependent or family member.
The official spoke on condition of anonymity because the official was not authorized to provide personal information.
Amy Biondi and her husband Steve were visiting Washington from Long Island with their daughter and a friend and tried to ask officers for help with a parking meter when they were told there was a situation they had to deal with. The door to the FRC was opened, and an officer could be heard repeatedly shouting, "Put the gun down, put the gun down."
"Next thing you know there are police officers swarming the area," said Biondi, 45, a massage therapist from St. James, N.Y.
The family didn't get a close look inside, but they said the man that officers were talking to seemed to comply immediately.
Groups aligned with conservative causes lambasted the shooting, but so did a coalition of more than two dozen organizations promoting gay, lesbian and transgender rights, which said it rejected and condemned the attack.
White House spokesman Jay Carney said the president, who was traveling in Iowa Wednesday, was informed of the shooting shortly after 1 p.m.
"The president expressed his concern for the individual injured in the shooting and his strong belief that this type of violence has no place in our society," Carney said.
Romney said in a statement that he was appalled. "There is no place for such violence in our society," he said. "My prayers go out to the wounded security guard and his family, as well as all the people at the Family Research Council whose sense of security has been shattered by today's horrific events."
The headquarters of the FRC is in the city's bustling Chinatown neighborhood, near the Verizon Center, the Smithsonian National Portrait Gallery and several museums, restaurants and shops.
In the past month, the FRC had forcefully defended Chick-fil-A President Dan Cathy for his remarks in opposition to gay marriage, which brought the fast-food chain to the forefront of the nation's culture wars.
Mariner said he did not know Corkins well or have any conversations with him about the Chick-fil-A controversy or other political issues of interest to the gay community.
"I really only talked to him about volunteering, so I couldn't say anything about anything else," Mariner said.
Associated Press writers Ben Nuckols and Lolita Baldor in Washington and Matthew Barakat in Herndon, Va., contributed to this report.