Stand on Zanzibar, by John Brunner.
It was written back in the 60s or 70s, but it did a remarkable job of predicting the future we now inhabit, including computer viruses, our ridiculous American obsession with guns, carried to its illogical extremes, and mad, unexplained mass murderers called "muckers", from "run amok". Its been a long time since I read it, so my memory of it may be imperfect; but I didn't refresh my memory of it by looking it up in Wiki. I believe it had a sequel too, "The Sheep Look Up", which I also read.