The most recent example is certain Eastern European politician best known for corruption, purging opposition, making headlines together with certain Russian president last year, now seen as the saint, because for some simpletons enemy of their enemy becomes their friend.
The only school shooters I can remember the names of are the Columbine shooters and I'd say that's mostly due to the fact they were the first in the modern school shooter era (depressing reality). Perhaps that fame helped fuel other shootings, but I can't name a single other one out of the many since then.
I'm sure the fact that we're so used to acts of violence in the US on a regular basis is a contributing factor. At this point you'd have to do something pretty horrendously bad to go down in infamy. On the other hand, if it were an act (without innocent casualties) committed against say a financial, insurance institution or some other disliked entity, they could become a folk hero.