Floyd Corkins, who allegedly shot a security guard Wednesday at the Family Research Council, has been charged in a two-count criminal complaint with a federal weapons violation and a local charge of assault with intent to kill while armed.

An FBI affidavit filed in the case by FBI Special Agent Garrett Nabors provides more details about the shooting. Security guard Leo Johnson wrestled Corkins to the ground, even though he had been shot in the arm.

Washington Police Chief Cathy Lanier and the FBI have praised Johnson for preventing more bloodshed.

Nabors' affidavit says that Corkins entered the Family Research Council headquarters building in downtown Washington and said, "I don't like your politics."

"Based on a review of the surveillance video from the Family Research Council, I know that after Corkins interacted with Mr. Johnson, Corkins retrieved a firearm from his backpack and pointed it at Mr. Johnson," Nabors writes.

"Corkins then began shooting at Mr. Johnson, striking him in the arm. After being wounded, Mr. Johnson moved towards Corkins, wrestled the firearm away from Corkins and subdued him." Nabors says.

"When I told him his actions were heroic in protecting his colleagues, he told me that he just reacted in the way he thought anyone at FRC [Family Research Council] would have responded," said FRC President Tony Perkins in a statement.

Perkins met with Johnson last night after he underwent surgery for the gunshot wound to his left arm.

Corkins, who told FBI agents that he acted alone, was allegedly armed with a Sig Sauer 9mm handgun and carried with him two magazines, 50 rounds of 9mm ammunition, and fifteen sandwiches from Chick-fil-A. Federal law enforcement officials tell ABC News that the firearm was purchased legally.

"A senior executive of Chick-fil-A, Inc., recently announced publicly his opposition to same-sex marriage. This announcement received substantial publicity," Agent Nabors writes. "I know further that the Family Research Council is a Christian conservative policy organization which supports traditional marriage."

The Family Research Council was founded in 1983 by James Dobson. Today, under Perkins, the council is vocal lobbying group for conservative Christian social issues, including opposition to abortion and gay marriage.

FBI agents conducted a search of Corkins' car, which he left at a Metro stop before heading into Washington. They also interviewed his parents.

"Corkins' parents informed the FBI Special Agents that Corkins has strong opinions with respect to those he believes do not treat homosexuals in a fair manner," says the affidavit.

Corkins, who graduated from George Mason University in Virginia with a master's degree in education and human development in 2006, had recently been volunteering at The D.C. Center for the LGBT Community, a community center for lesbian, gay, bisexual and transgender people in Washington.

Corkins was ordered detained without bond at his initial appearance Thursday afternoon. Corkins appeared subdude and was dressed in an oversized Tyvek jumpsuit with a hood. Corkins has been ordered to undergo a mental evaluation by the federal magistrate.

Corkins told the court he could not afford a defense attorney with only $300 in his bank account. David Bos, the federal defender appointed to represent Corkins declined to comment on the case.

Corkins is set to appear again in court on Friday, August, 24 for a preliminary hearing and detention hearing.

Corkins faces 10 years in prison for the federal offense and 30 years for the D.C. offense if convicted.

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