Martin Sheen is behind a new documentary series which claims to offer new evidence that O.J. Simpson was not guilty of the murders of Nicole Brown Simpson and Ronald Goldman. Sheen will be the executive producer and narrator of ‘Hard Evidence: O.J. Is Innocent’, planned to air on the Discovery Channel spin-off Investigation Discovery. It’s said that the six-part show will reveal 'critical new evidence’ about the murders in Brentwood, Los Angeles, back in 1994, and is based on 20 years of investigation by Texas private investigator William C. Dear, who penned the book 'O.J. Is Innocent and I Can Prove It’, published in 2012.