George Zimmerman says he is vetting bids after closing an auction for the handgun he used to kill unarmed black teenager Trayvon Martin.

The former neighbourhood watch volunteer – who was acquitted over the 2012 killing – revealed on his blog that the sale had been successful, but did not give any details.

The website believed to be the venue for the auction, United Gun Group, tweeted that there were two auctions running simultaneously, one for pre-qualified buyers and a “fake” one for the public.

Bids on the fake site visible to the public went as high as $138,900 before it was deleted on Wednesday.

Trayvon Martin

Trayvon Martin, 17, was shot and killed in 2012

Mr Zimmerman had set a minimum bid of $100,000 for the 9mm Kel-Tec PF-9 pistol.

He told WOFL TV station the pistol was returned to him by the US Justice Department, which had taken it after he was acquitted of the 17-year-old’s death.

Critics had called the auction an insensitive move to profit from Trayvon’s death.

Leading gun auctioneers refused to sell the weapon, describing the sale as “despicable”, and an eBay advert attracted false bids of up to $65m.

Seminole County Sheriff's Office booking photo of George Zimmerman

George Zimmerman was acquitted of the killing in 2013

Mr Zimmerman, 32, said he was defending himself under Florida’s “stand your ground” law when he killed the teenager in a gated community near Orlando.

Trayvon, who lived in Miami with his mother, was visiting his father at the time.

The acquittal sparked protests across the US and a national debate on race relations.

The Justice Department later decided not to prosecute Mr Zimmerman on civil rights charges.

Mr Zimmerman had stated that part of the proceeds from the sale would go towards fighting against violence by the Black Lives Matter movement against law enforcement.

The original auction also claimed proceeds would go towards anti-gun rhetoric by Democratic presidential candidate Hillary Clinton and ending the career of Angela Corey, who led the prosecution against Mr Zimmerman.