Image copyright AP Image caption The Kel-Tec PF-9 would normally cost about $350 new

The handgun used to kill unarmed black teenager Trayvon Martin in 2012 has been sold for $250,000 (£172,000), US media say.

The gun was put up for auction by George Zimmerman, who fired the shot but was acquitted of Trayvon's murder.

US media said Mr Zimmerman had backed out of a deal for $150,000 to take the higher price.

The killing was instrumental in launching the national Black Lives Matter social movement.

The sale of the gun drew criticism from those saying Mr Zimmerman, 32, was seeking to profit from the killing. Gun rights advocates say he was exercising his legal rights under US law.

Hoax bidders

The site that hosted the auction, UnitedGunGroup.com, on Saturday confirmed the amount the Kel-Tec PF-9, 9mm pistol had fetched, according to AFP news agency. The pistol sells new for about $350.

The Florida neighbourhood watchman had himself told the KTNV station he was accepting the sum.

Denny Honeycutt, a Florida bar owner who said he had agreed a price of $150,000, told the Daytona Beach News-Journal that Mr Zimmerman had reneged on the deal.

"I thought he was a man of his word," Mr Honeycutt told the paper.

He said the buyer was a woman who had wanted the gun as a birthday present for her son.

But Mr Zimmerman said he would not reveal the buyer's identity, adding: "The winning bidder will ultimately decide if they want their information to be maintained in confidentiality."

UnitedGunGroup.com hosted the auction after another site, GunBroker, backed out, saying it wanted no part in the listing. Mr Zimmerman called GunBroker "Nazi loving liberal liars".

The auction initially attracted hoax buyers, with bids as high as $65m and bidders with names such as "Racist McShootface".

Mr Zimmerman said some of the proceeds would serve to "fight [Black Lives Matter] violence against law enforcement officers".

But Martin family lawyer Benjamin Crump told Fox the sale was "offensive, outrageous and insulting".

Trayvon Martin was walking home from a shop in Sanford, Florida, in February 2012 when there was an altercation with Mr Zimmerman.

Mr Zimmerman said he had fired in self-defence. He was charged and acquitted of second-degree murder and manslaughter.