New evidence gleaned from the investigation into last week’s Sony Pictures hack — which resulted in the online leak of at least five major films — suggests the attack was set off by North Korea, possibly in retaliation for a forthcoming comedy about assassinating Kim Jong-un.

Researchers investigating the hack have uncovered malicious code with extreme similarities to a code used in an attack against South Korean banks and television stations in 2013, “people briefed on the investigation” told The Wall Street Journal Monday.

The discovery lends further evidence to the theory held by Sony, the cybersecurity firm FireEye brought in to investigate, and the FBI that North Korea launched the attack as a response to the upcoming Sony film “The Interview,” which stars Seth Rogen and James Franco in a comedic attempt to assassinate North Korean dictator Kim Jong-un for the CIA. (RELATED: James Franco And Seth Rogen Plot To Kill Kim Jong-un In ‘The Interview’)

Sony Pictures Entertainment computers crashed last Monday after displays showed a red skull with the phrase “Hacked By #GOP [which reportedly stands for Guardians of Peace]” followed by a warning claiming the hack was “just the beginning.” The hack resulted in the online leak of five new DVD screeners including “Fury,” “Annie,” “Mr. Turner,” “Still Alice” and “To Write Love on Her Arms,” which have since been downloaded more than one million times on file-sharing sites.

Passports, bank account information and emails belonging to employees were also compromised in the attack, according to The Hill.

The North Korean government has been highly critical of the film since its announcement, describing it as “undisguised sponsoring of terrorism” and “an act of war” in a letter to the U.N. earlier this year. North Korean leaders alleged that a film about assassinating a foreign leader “mirrors what the U.S. has done in Afghanistan, Iraq, Syria and Ukraine.”

An email claiming to originate from the attackers sent to The Verge Monday describes the film as “dangerous enough to cause a massive hack attack.”

“Sony Pictures produced the film harming the regional peace and security and violating human rights for money,” the email said. “The news with ‘The Interview’ fully acquaints us with the crimes of Sony Pictures. Like this, their activity is contrary to our philosophy. We struggle to fight against such greed of Sony Pictures.”

“The Interview” releases in theaters Dec. 25.

Follow Giuseppe on Twitter and Facebook