Zimmerman confirmed with ABC News that the new listing with the United Gun Group is legitimate. The starting bid is $100,000 with a $500,000 "buy it now" price.
The listing is titled "George Zimmerman's Gun used 2/26/12." The date is the day Martin died after he was fatally shot by Zimmerman in Sanford, Florida, while Zimmerman was volunteering for a neighborhood watch program.
The introduction for the listing, presumably written by Zimmerman, says the gun has recently been returned to him by the Department of Justice. The Kel-Tec brand 9-millimeter pistol is fully-functional and has Zimmerman's case number written in silver permanent marker, Zimmerman wrote, calling the gun a "piece of American history."
Zimmerman claims many have expressed interest in owning and displaying the gun, including the Smithsonian Museum in Washington, D.C. The museum quickly denied his claim, tweeting on Thursday it "never expressed interest" in collecting the firearm.
We have never expressed interest in collecting George Zimmerman’s firearm, and have no plans to ever collect or display it in any museums— Smithsonian (@smithsonian) May 12, 2016
He said that while offers have been presented to him to purchase the gun, he wasn't "comfortable" with the "fashion" the gun would be used in.
Zimmerman guarantees the the validity and authenticity of the firearm and wrote that a portion of the proceeds will be used to fight violence against police officers by the Black Lives Matter movement.
The 32-year-old, who was acquitted of second-degree murder and manslaughter in the summer of 2013, also wrote that the proceeds will go toward "the demise" of the career of Angela Corey, the prosecutor assigned to Zimmerman's case, and to combat Hillary Clinton's anti-firearm campaign rhetoric.
Clinton later tweeted a message of support to Martin's mother.
Sybrina, you and all mothers of gun violence victims have taught us hate will never win. Thinking of you today. https://t.co/FnsaKtq1hd -H— Hillary Clinton (@HillaryClinton) May 12, 2016
At one point early Friday, the bidding for the gun surpassed $65 million, The Associated Press reported, with the leading bidder using the name "Racist McShootFace." Other screen names of bidders on the site included "Donald Trump," "shaniqua bonifa," and "Tamir Rice," the name of the 12-year-old who was shot and killed in 2014 by Cleveland police as he played with a pellet gun, according to the AP.
United Gun Group began hosting the auction Thursday after another gun website, GunBroker.com, took down the listing within an hour after it was posted, saying it wanted "no part" of it or the "publicity it is receiving," the AP reported.
"The firearm for sale is the firearm that was used to defend my life and end the brutal attack from Trayvon Martin," Zimmerman wrote on GunBroker.com before the post was removed.
Zimmerman's name has remained in headlines since his acquittal. He was charged with assault based on complaints from two girlfriends, who both later refused to press charges. Zimmerman's ex-wife accused him of smashing her iPad during an argument days after she filed divorce papers, but no charges were filed based on lack of evidence.
Zimmerman's acquittal in the killing of Trayvon Martin sparked country-wide protests and sparked a national debate over the deaths of black men and boys by law enforcement.