Just a week before its scheduled Tribeca Film Festival premiere, producers of Alex Gibney's "No Stone Unturned" pulled the documentary about the 1994 murder of six men in Northern Ireland from the festival over legal issues.

The film was to premiere April 23 at the festival, where "No Stone Unturned" would have been one of the more high-profile documentaries debuting. Producer Trevor Birney said in a statement he was "bitterly disappointed" to withdraw the film because of "ongoing legal issues relating to the subject matter of the film."

"No one will feel this disappointment more than the families at the center of the film, whose quest for justice has been both inspiring and unstinting these last 23 years," said Birney. "It is our deepest hope that these sensitive issues can be resolved as soon as possible so that we can share this important film with the world."

The New York festival said it was notified Friday and that it shared in the disappointment of the film's producers and Gibney. Gibney won an Academy Award for his 2007 documentary "Taxi to the Dark Side."

"No Stone Unturned" investigates the 1994 case in which six were killed and five wounded while watching a World Cup soccer match in a Loughinisland, Northern Island, pub. The police investigation, the film's description states, "was perfunctory at best" and the case remained unsolved.

"'No Stone Unturned' is a powerful story and so is the attempt to silence it," Gibney wrote on Twitter. "The truth will be told."