Harry Potter movie executives are angry and have launched an investigation into how the latest movie "The Goblet Of Fire" was released on the internet even before it was released in British theatres.

According to contactmusic.com, fans have been able to download the movie for free on the internet days before its official release date.

In an effort to nab possible copyright violators, ushers at certain theatres have been given night-vision goggles. This enables them to spot viewers trying to record pirated copies of the film with hidden video cameras.

A source said: "The situation is way out of control. The fact that the latest Harry Potter film has been leaked on to the web is a huge blow for everyone concerned.

"The public should be worried too because any of these downloads which make it onto pirated DVDs help to fund organised crime like drugs and prostitution."