Last Updated May 12, 2016 11:03 PM EDT
NEW YORK -- A firearms auction website removed a listing for the gun Florida man George Zimmerman used to kill teenager Trayvon Martin minutes before the weapon was scheduled to be auctioned Thursday.
Zimmerman wrote on the auction page that the 9 mm Kel-Tec PF-9 pistol was recently returned to him from the U.S. Department of Justice. The starting bid for the weapon, which he called an "American Firearm Icon," was $5,000.
"What I've decided to do is not cower," Zimmerman told Orlando television station WOFL. "I'm a free American. I can do what I want with my possessions."
The auction was set to begin at 11 a.m., but the listing was removed before any bids could be made. The website, GunBroker.com, said in a statement Thursday afternoon that it reserves "the right to reject listings at our sole discretion, and have done so with the Zimmerman listing."
"We want no part in the listing on our web site or in any of the publicity it is receiving," the company said in its statement.
A person claiming to be Zimmerman posted the weapon on another website, UnitedGunGroup.com, about three hours later. CBS News had not verified that the new listing is authentic.
Thursday evening, the second website -- which calls itself a "social market place for the firearms community -- decided to pull the listing, CBS affiliate WKMG reported.
"As an organization, we stand by the rule of law and, while no laws have been broken, we do not feel like it is in the best interest of the organization to continue to host this sale on our platform," the company said in a press release. "Our mission is to esteem the Second Amendment and provide a safe and secure platform for firearms enthusiasts and law-abiding citizens; our association with Mr. Zimmerman does not help us achieve that objective."
Trayvon Martin's parents still view Zimmerman's gun as the murder weapon.
"How could you possibly try to make money off of killing of their child?" Benjamin Crump, the family's lawyer, told CBS News. "It is just ... Imagine if it was your child."
The 32-year-old Zimmerman wrote on the auction page that a portion of the proceeds would be used in opposition to the Black Lives Matter movement and Hillary Clinton. He also noted that Thursday marks exactly one year since a May 11, 2015, incident in which police say a man fired a shot at Zimmerman. Matthew Apperson has been charged with second-degree attempted murder in that case.
Zimmerman also wrote that the Smithsonian Institution "expressed interest" in the gun, a claim denied by the museum.
"No we're not collecting his gun, and no we've never requested it," Linda St. Thomas, a spokeswoman for the museum, told Crimesider.
Zimmerman was acquitted of second-degree murder following the 2012 shooting death of Trayvon Martin, an unarmed black 17-year-old boy. Zimmerman was a neighborhood watch volunteer who claimed the shooting was in self-defense.