A federal appeals court has approved additional review of a claim from a condemned killer that he's innocent of the notorious 1998 slaying of a black man chained to the back of a pickup truck and dragged along a bumpy rural East Texas road.

Attorneys for John William King argued to the 5th U.S. Circuit Court of Appeals that King's trial lawyer was deficient in presenting a case for innocence.

MORE | TDCJ Death Row info page for King

They contend only a few pieces of circumstantial evidence that could be innocently explained tied King to the scene of a fight that resulted in 49-year-old James Byrd Jr. being chained to the truck and fatally dragged.

King, now 42, who is currently on Texas' death row, is one of three white men convicted of the slaying.

Lawrence Russell Brewer was executed in 2011 and Shawn Berry is serving a life prison sentence.

12News spoke to James Byrd's sister, Betty Boatner, over the phone on Wednesday. She said "It brings back a lot of memories of what took place and its a day by day process."

When asked about King, Boatner said: "I just don't understand why he's trying. When he was found guilty by a jury in trial."

Boatner told 12News Byrd left behind three children and four grandchildren.