So here we are again for another update on manga, this one was released around 2007, so me talking about this manga three years after would be pretty much pointless. But to tell you the truth, right now, its manga is already at its third and last season. They also made a drama for this manga but haven't heard of an anime yet.
So to start things off Bloody Monday is the name of this manga. The story starts off with a scene a Russia, with two suspicious individual making a deal of some sort of chemical that would later be the reason why the title was named after. The chemical was tested at a train running, and as you've guessed, a lot or maybe all of the people died on that train. So a virus deal clinched in Russia on the Christmas eve. Purpose: unknown. Two clues: a mysterious lady "Maya", one of the gangsters, and "Bloody Monday", the keyword for the project. Then an incident happened in far-distant city of Tokyo. Fujimaru Takagi, a second grade student at Mishiro Gakuin high school, is commissioned to find out the truth by Public Security Investigation Bureau for his great ability as a super hacker. Now, Maya, approaching to Fujimaru, as his high school teacher...
Now the clues are all given to you, now its your turn to deduce on how the story unfolds. Its a story that would lead you to think and be more logical as there are a lot of twist and turns in this manga. Also it covers the field of technology that it would make you be more updated to the computer world. Be sure to start reading season one before you finish all the way to the last season.