George Zimmerman is auctioning the gun used to shoot Trayvon Martin

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George Zimmerman is selling the gun he used to shoot and kill Trayvon Martin, an unarmed African American teenager, in February 2012.

Zimmerman was later acquitted of murder. 

Now, Zimmerman, 32, is selling what he calls a "piece of American history." 

"The firearm for sale is the firearm that was used to defend my life and end the brutal attack from Trayvon Martin on 2/26/2012," Zimmerman writes, according to the auction site.

"Now is your opportunity to own a piece of American History. Good Luck." 

The gun is a Kel-Tec PF-9 9mm, according to the auction site. The opening bid is $5,000.

The auction begins Thursday morning. 

Zimmerman said a portion of the proceeds from the sale would go toward fighting "Black Lives Matter violence against law enforcement officers."