Wolverine
The FBI have been called in to investigate the leaking of X-Men Origins: Wolverine onto the internet.
Althought the film has now been removed it is believed that the film, which sees Hugh Jackman reprise the role of Logan, had been downloaded 100,000 times.
In a statement, 20th Century Fox said: "The source of the initial leak and any subsequent postings will be prosecuted to the fullest extent of the law. The courts have handed down significant criminal sentences for such acts.
"Such theft undermines the enormous efforts of the filmmakers and actors and, above all, hurts fans of the film."
The studio added that both the FBI and the Motion Picture Association of America are "actively investigating" the incident.
The leaked material was an incomplete and early version of the film with several special effect scenes and musical score missing.
X-Men Origins: Wolverine is released 29th April.