X-Men Origins: Wolverine made an unauthorized debut on the Internet on Tuesday, even though the film isn’t set for release in the U.S. until May 1. Wolverine, a spinoff of the X-Men film franchise, stars Hugh Jackman and is directed by Gavin Hood.

Web sites that managed to sneak a peek at the illegal download described it as a nearly complete, high-quality copy, but 20th Century Fox, the studio behind the film, tells a different story. In a statement released Wednesday, the studio said that the leaked Wolverine included temporary sound and music and was missing effects and some scenes, with other scenes unedited. The studio said it would be able to determine the source of the leak because of forensic marks on the unauthorized copy.

“We immediately contacted the appropriate authorities and had it removed,” though once a film begins circulating online, it can be difficult to stamp it out……The FBI and the MPAA (Motion Picture Association of America) also are actively investigating this crime. We are encouraged by the support of fansites condemning this illegal posting….”