George Zimmerman, the Miami neighbourhood watch volunteer who provoked a storm after he shot dead an unarmed black teenager in Florida in February, apparently has black ancestry.
A photo aired by CNN shows a black-skinned man that Orlando attorney Mark NeJame says was George Zimmerman's great-grandfather.
It appears to support what Zimmerman's family has been saying for months: that Zimmerman has black-skinned relatives and was raised in a mixed-race family.
His views on race are important because Zimmerman, 28, is awaiting trial in Sanford on a second-degree murder charge. He shot and killed Trayvon Martin, an unarmed black 17-year-old, on February 26 as the teen walked through a gated community.
Trayvon's father, family lawyers and critics say Zimmerman is guilty of racial profiling and murder.
But Zimmerman told police he acted in self-defence, pulling the trigger of his nine-millimetre handgun only after Trayvon confronted him, knocked him to the ground and began hammering his head onto a sidewalk.
National civil rights leaders travelled to Sanford in March, demanding Zimmerman's arrest. They included Al Sharpton, the Rev Jesse Jackson and the national president of the National Association for the Advancement of Colored People (NAACP).
Zimmerman's family members, however, insist he is no racist.
NeJame appeared on CNN on Thursday with an old photo. He told the 24-hour news channel that the photo originated from a member of Zimmerman's family and was provided by a friend.
The Orlando Sentinel could not independently verify its authenticity.
The photo shows a middle-aged black man in a shirt and tie with a baby on his lap and a young woman standing behind him.
The man is Zimmerman's great-grandfather, NeJame told the network; the baby is Zimmerman's mother; and the young woman is his grandmother.
