Trayvon Martin's friend Rachel Jeantel is asked by Piers Morgan if there anything she wished she'd said on the stand, this was her reply. Credit: CNN

A STORM of outrage has swept the internet after two men went to a Halloween party dressed as the central characters in one of America's most controversial killings - the shooting of black teenager Trayvon Martin by George Zimmerman.

The photo, featuring the man dressed as Trayvon complete with blackface makeup and a bloodstained hoodie, swiftly went viral after being posted to Facebook by Caitlin Cimeno, who also appears in the picture.

Cimeno, of Florida, deleted her account after a barrage of abuse from people disgusted at the apparent insensitivity - a sentiment not helped when her brother Greg Cimeno, who portrayed George Zimmerman, responded to adverse comments about the image.

"Anything for the laugh," declared Cimeno. When one of Caitlin's friends wrote that the photo was "Not too funny," Greg replied, "Not too funny. It's f@^*ing hilarious!!!"

These Trayvon Martin & Zimmerman costumes make me hate all of you. Blatant racism. — Darlene Fontes (@comeheagorgeous) October 28, 2013

Nothing like a little Trayvon Martin blackface to up the offensive Halloween costume ante: http://t.co/uAlxX9JPfi — Phil Jimenez (@Philjimeneznyc) October 27, 2013

The man portraying Trayvon has been identified as William Filene, 25.

The outrage comes just after an Australian woman unwittingly sparked an online backlash and was accused of being racist when she threw a 21st birthday party with an African theme - and posted pictures of partygoers with made-up coloured faces.

Much of the abuse in that case came from Americans, who are particularly sensitive to the use of blackface and its racist overtones.

The case of Trayvon Martin has been mired in allegations of racism since the unarmed 17-year-old African American was shot dead by Zimmerman in February 2012.

Zimmerman, a neighbourhood watch volunteer, asserted he thought Trayvon was a criminal and that he shot him in self-defence during a desperate struggle - while others accused the 30-year-old of gunning down the teen in cold blood.

The incident at Twin Lakes gated community in Sanford, Florida, became international news and reached headlines again when Zimmerman was fou nd not guilty of second-degree murder and manslaughter in July this year.

Rallies across America for Trayvon Martin

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I just saw a Trayvon Martin/George Zimmerman Halloween costume. That is literally beyond disgusting. People make me so sick. — khendallllll. (@pashh15) October 27, 2013