US confident Kim Jong-Un's regime behind Sony cyber attacks because they 'got sloppy'

FBI chief ends speculation about who was behind the mass leak of classified emails and unreleased music and films

The FBI say North Korean dictator Kim Jong-un's nation is responsible for the Sony hack (Reuters)

FBI director James Comey has officially put an end to questions over who was responsible for the embarrassing cyber attacks on Sony Pictures, which led to James Franco and Seth Rogen's comedy The Interview being shelved.

Comey said that the attack was clearly from North Korea, as the attacker posted material from servers which are only used by servers in that country and that the hackers "got sloppy".

Pyongyang has denied committing the attack, done under the moniker "Guardians of Peace", but described it as "righteous".

The hackers struck in the run-up to the release of controversial comedy, The Interview, which included a gruesome scene showing Kim Jong-un being killed.

Kim Jong-un was the focus of fun in the Sony film (AP)

The release of the film was briefly shelved, attracting an avalanche of criticism that the US had bowed to terrorists. It was later put on limited release in cinemas and distributed online.

In June 2014, North Korea threatened "merciless" retribution upon the US if the film's release went ahead.

Hackers released embarrassing private emails, including one in which producer Scott Rudin branded Angelina Jolie a "minimally talented spoiled brat".