How the world would react if the International agencies discovered that every 21st catastrophic even was caused by a mysterious Hacker, such as the attacks of 9/11 and the Rab'a massacre and so on,

Question: How would the world react if the International agencies discovered that every 21st catastrophic even was caused by a mysterious Hacker ,such as the attacks of 9/11 and the Rab'a massacre and so on , and the warry thing that his whereabouts cannot be tracked with the evidance we have and that he has made a video about him planting a nuke in the heart of a random US city , and how would the world react if he ended the video saying "I will have fun seeing millions die online" , and then the nuke detonate in Los Angeles Killing more than 780000 People , and then he releases another video contaning him saying "the next destination is England" and start laughing menacingly ,and then after a few days a nuke detonate in Manchester killing more than 500000 people ,while the authoritiesstill can't track him, and then yet again the Hacker uploads a video saying the next destination is Turkey , and then yet again a bomb detonate near Armenia in Turkey killing more than 250000 people, and then he uploaded a video saying "Germany next" , and after just 5 days from the announcement ,a nuke detonate in Berlin killing more than 1200000 people ,and he uploaded yet another video saying "we will go back to America" and after 3 days the FBI HQ blow up with a nuke planted inside it decimating the head quarters and the city it self , and at the End ,he disappears with another Video and it'stitle is Mission completed and then he disappear for good, and after 25 years the governments couldn't even know were he lives then afyer all those years he releases a videoand says in it just "my name is Solomon" and then he apprehend himself to Justice for the feel of guilt?