For more than 100 years, there has been a concerted effort to rehabilitate Leo Frank from a fiendish and perverted sex killer into a holy religious martyr of Southern anti-Semitism, but modern scholars have solved the Mary Phagan murder mystery by using Leo Frank's testimony at the trial. The judge and jury sentenced Leo Frank to death with a vote of 13 to 0. That unanimous vote of guilt, rendered against Leo Frank, was upheld by every appeals court in the United States.
Leo Frank was sentenced to hang, three times, by three different courts during his appeals, but the outgoing Governor, John M. Slaton, commuted the June 22nd, 1913, death sentence of Leo Frank to life in prison. The leadership of the Atlanta government were so incensed by the clemency Governor Slaton gave to the serial rapist-pedophile and convicted child strangler. The anger came from the fact, Governor John Slaton, was a law partner and part owner of the firm that represented Leo Frank at his trial. So the Governor basically commuted the death sentence of his own law client. It was a grotesque conflict of interest, because the Governor was disqualified from using his executive privilege for a client.
You can read the fascinating, original Atlanta newspaper reports of Leo Frank Case, online at the Internet Archive, concerning how the case was treated in the media through, the Atlanta Constitution, Atlanta Journal and Atlanta Georgian, which also posted the trial testimony.
Leo Frank had a fair trial according to Georgia Supreme Court and United States Supreme Court. The Leo Frank trial brief of evidence, is published online.
The best sites for information on the Leo Frank case are "The Internet Archive" and "Live Leak"