Transcript for Researchers discover 'link' between North Korea and global cyberattack

Our chief investigative correspondent Brian Ross and your sources are are really concerned about this report this morning they believe this could lead to clues that could lead to the uncovering of an informant a human source inside ices. Who has been vital in detecting plots that they were working out far from over and there are also new developments in the cyber attack that affected a hundred. And fifty countries we're hearing that North Korea. Has the plane that's they appear to be the chief culprit here law enforcement authorities intelligence agencies around the world say. The track could lead to North Korea that the computer code. That produce the so called wanna cry attack would these ominous messages appears to have similarities to the code used by North Korea in an attack on international banks last year. It could be someone else using North Korean code researchers say but the country has a long record of computer criminality. And while there's still no official attribution of who was behind this massive attack the tally of targets continues to grow. More than 300000. In 150. Countries. Auto plants factories railroads are on the world. And FedEx in the US were all hit has anybody pay this ransom well some people have about 243. People were told appear will follow that happens directions to pay 300 dollars or more to have their files freed. But officials say none of those companies got the key to get the files back to that was kind of a second scan all right thanks so much.

This transcript has been automatically generated and may not be 100% accurate.