North Korea is alleged, behind the massive cyber-attack that struck the entire world by infecting no less than 200.000 computers from all around the world, reports one of the world’s most influential cyber-security companies.

“It is similar to North Korea’s backdoor malicious codes”, said Simon Choi, who had worked many years as a senior researcher of North Korea’s hacking capabilities.

Europol elaborated on its past findings about how much hackers had managed to extort money from the victims of the cyberattack, saying some 243 payments of a total of about 63,000 dollars had been made since the start of the attack on May 12.

Symantec, Intezer Labs of Israel and Russia’s Kaspersky Lab on Monday agreed that a considerable part of the “WannaCry” ransomware is identical with a hacking program used by the Lazarus group, which has ties to North Korea.

While Choi’s speculation may deepen suspicions that the nuclear-armed state is responsible, the evidence is still far from conclusive.

Researchers believe North Korea may be behind the global cyberattack that targeted 150 countries last week, affecting more than 300,000 computers.

The virus encrypts a computer’s files and will only decrypt them in return for a payment, typically via Bitcoin, an online currency. Failure to pay would leave the data scrambled and probably beyond fix.

Experts say the rapid spread of the worm globally suggests it did not rely on phishing, a method whereby an email is sent to people with the aim of having them click on infected documents or links.

Specially, no United States federal systems are affected, he said.

Lazarus was also implicated in the 2014 hack of data from Sony Pictures, in apparent retaliation for its release of the film “The Interview” that mocked North Korean leader Kim Jong-un.

Choi introduced that he unintentionally contacted a North Korean hacker a year ago, stumbling onto a plot to develop a type of ransomware.

In early 2015, the White House announced a new set of economic sanctions to penalize North Korea over its involvement.

Researchers have said that some of the code used in Friday’s ransomware, known as WannaCry software, was almost identical to the code used by the Lazarus Group, a group of North Korean hackers who used a similar version for the hack of Sony Pictures Entertainment in 2014 and last year’s hack of Bangladesh Central Bank. One code sample is from the early version of WannaCry, and the other is from the malicious software used by Lazarus, called Contopee. It’s entirely possible some other hacking group found and copied code from Lazarus’ tools.

In China, foreign ministry spokeswoman Hua Chunying said she had no information to share, when asked about the origin of the attack and whether North Korea might be connected. Fewer than 10 US organizations have reported attacks to the Department of Homeland Security since Friday, a USA official told reporters on Tuesday.