The director passed away on Saturday (21Feb15) from complications stemming from diabetes.
Sinofsky's filmmaking partner Joe Berlinger tells Variety.com, "The extraordinary adventures we had on the road and the deeply stimulating experiences we had in the editing room were life-changing for all of us who knew him thanks to his wisdom and fervor to change the world."
He began his filmmaking career with Berlinger with 1992 documentary Brother's Keeper, and they re-teamed to tell the story of the West Memphis Three - three Arkansas teenagers who were convicted of killing three eight-year-old kids in 1993.
The acclaimed 1996 documentary Paradise Lost: Child Murders at Robin Hood Hills featured a score by Metallica, who backed the trio's cause to clear their name and be freed after learning they were fans of the band. It spawned two sequels and the third film, Paradise Lost 3: Purgatory, was nominated for an Academy Award in 2012, just months after the West Memphis Three were released as part of a controversial plea deal.
Sinofsky reunited with the metal group to make 2004 documentary Metallica: Some Kind of Monster, which detailed the troubled recording process as the band worked on their album St. Anger.