Oscilloscope Laboratories has acquired North American rights to The Matador director Richard Shepard’s documentary I Knew It Was You.

The film explores the life of the little-known actor John Cazale, whose death from cancer in his early 40s ended a potentially brilliant career.

Cazale played the hot-headed Fredo Corleone in The Godfather and The Godfather: Part II and starred in three other acclaimed films from the 1970s – The Conversation, Dog Day Afternoon and The Deer Hunter.

I Knew It Was You premiered at Sundance and aired on HBO June 1. The ubiquitous Brett Ratner produced alongside Stacey Reiss.

The film features interviews with such Hollywood luminaries as Al Pacino, Gene Hackman, Robert De Niro, Richard Dreyfuss, Meryl Streep, and Sidney Lumet.

“Oscilloscope is the Fredo of independent film, so it’s an honour to put this film out,” O-Scope head Adam Yauch said. O-Scope will release the DVD in the autumn.