(CNSNews.com) – The domestic terrorism attack by a lone gunman against the Family Research Council (FRC) headquarters in Washington, D.C. in 2012 is included in a new exhibit at the National Museum of Crime & Punishment.

The gun used by domestic terrorist Floyd Lee Corkins is a part of the exhibit. Corkins admitted to authorities that he targeted the Family Research Council because it was cited on the 'Hate Map' of the Southern Poverty Law Center website. (CNSNews.com/Penny Starr)

“The exhibit stands as a reminder that in a civil society we must never allow free and open debate to be shut down through acts of terrorism,” said Lt. Gen. (Ret.) William G. “Jerry” Boykin, the executive vice president of the Family Research Council.

The “Domestic Terrorism and Hate Crimes” exhibit, which opened on Wednesday, Mar. 18, includes evidence from the attack by Floyd Lee Corkins, who entered the FRC building on Aug. 15, 2012, brandishing a gun and planning to commit mass murder.

He later admitted to authorities that he learned of the FRC from a “Hate Map” posted on the Southern Poverty Law Center’s website, which describes the FRC as “Anti-LGBT,” anti-lesbian, gay, bisexual and transgender.

A new exhibit at the National Museum of Crime and Punishment in Washington, D.C. features evidence from the attack on the Family Research Council in 2012 by a gunman who was later convicted of several felonies, including domestic terrorism. The exhibit includes a photo of Leo Johnson, the man who stopped the gunman and saved countless lives. In the foreground is some of the ammunition found on the gunman after the attack. (CNSNews.com/Penny Starr).

Corkins, who was convicted of several felonies, including domestic terrorism, is serving 25 years in prison for his crime.

The new exhibit includes the gun and spent shell casings from the three shots fired by Corkins. It also has his backpack that he had filled with Chick-fil-A sandwiches that he had intended to push in the faces of his victims, according to the exhibit signage.

The wrappers for those sandwiches are on display in an evidence bag and were a part of the attack, Corkins said, because of the stance taken by the owner of the food franchise in support of traditional marriage.

“The Chick-fil-a sandwiches were discarded but the wrappers were kept and taken into evidence,” the exhibit signage says.

The gunman who planned to attack staff at the Family Research Council also carried a bag of Chick-Fil-A sandwiches, which he later said were to smash in the faces of his victims. Floyd Lee Corkins opposed the owner of the food franchise reportedly for his stance in support of traditional marriage. (CNSNews.com/Penny Starr)

There’s also a photo in the exhibit of Leo Johnson, the building operations manager who was acting as a security guard on the day of the attack. Although he was shot in the arm, Johnson was able to subdue Corkins until police and the FBI arrived on the scene.

“This museum exhibit is a testament to Leo Johnson’s heroism, the dedication of the law enforcement officers working the case and, most importantly, the protective hand of the Lord,” Lt. Gen. (Ret.) Jerry Boykin, the FRC executive vice president, told CNSNews.com. “The exhibit stands as a reminder that in a civil society we must never allow free and open debate to be shut down through acts of terrorism.”

“Floyd Corkins, through the inspiration of the Southern Poverty Law Center, intended to use mass murder as a means to silence those who uphold marriage as the union of a man and a woman,” Boykin said. “As Americans we will have our disagreements, but we must all boldly stand up for the freedom to debate these issues without giving into fear and intimidation.”

The signage for the FRC portion of the exhibit does not include any reference to the Southern Poverty Law Center. Janine Vaccarello, chief operating officer for the museum, told CNSNews.com that limited space required that curators be selective about what was included in the exhibit.

“The purpose of this story [on FRC] was to review the event itself as a hate crime but not details regarding the criminal, or criminal psychology,” Vaccarello said. “We simply had too much material to cover and limited space.”

Other items in the domestic terrorism exhibit include rubble from the World Trade Center terror attack on Sept. 11, 2001; a running bib and backpack from the Boston Marathon terror attack; a rifle confiscated from the Virginia Jihad Network in 2003; letters from the Unabomber; a rope from a lynching; and the book written by the mother of Matthew Sheppard, a homosexual man who was beaten and left to die by two men who were convicted of his murder.

“It’s an honor to install an exhibit that affects so many people,” Vaccarello said in a press release issued on the opening day of the exhibit. “It will be an emotional journey -- remembering where you were when 9/11 occurred or if you had a friend running in the Boston marathon.”

“It will also challenge museum-goers to re-examine their beliefs on what constitutes a hate crime, how history has been documented, and how prejudices have changed,” she said.

“In doing so, we hope to raise awareness and change behavior for the better,” Vaccarello said.

The FBI loaned the items to the museum for the FRC portion of the exhibit, which is scheduled to be in place for at least five years.