Man's identical twin confesses to murder he is serving time for

Karl Smith made a shocking confession on the witness stand in Chicago on Thursday - he admitted to a crime that his brother has served 13 years for, according to the Chicago Tribune.

"I'm here to confess to a crime I committed that he was wrongly accused of," Smith told the stunned court.

His 38-year-old identical twin, Kevin Dugar, has been in custody since 2003 over the killing of Antwan Carter.

The men have different names as Smith changed his name to his mother's maiden name, but when they were growing up, they acted as "one person", and became active gang members.

Even now the men cannot be distinguished easily other than by their prison clothes.

Smith is already serving a 99-year sentence for an armed robbery which ended in a six-year-old boy being shot in 2008, and has "nothing to lose" by confessing, Assistant State's Attorney said.

Smith only confessed to his brother in a letter three years ago, and then went on to sign a sworn confession in 2014, according to the Tribune.

Many are unsure as to whether the confession is real, but if a judge decides Smith's story is credible, his brother would be given a new trial for the killing.