Do you mean what problems can they cause or are you talking about actual documented incidents of them being used? I don't personally know of any studies suggesting that suppressors are or are not a problem so i don't want to just guess whether they are used in a significant percentage of crimes. Their potential should be obvious because of what suppressors are able to do. Able to mask or conceal the sound of the gun being fired. Lets not kid ourselves by pretending that the only use for suppressors is saving our hearing.
And in the absence of a suppressor, people never use guns in crimes for fear of alerting people.
And there are no other quieter alternatives than a suppressed gun for murdering someone, like bats, knives, suffocation, strangulation, a blunt object, scissors, poisons, drowning, ....
As for "Lets not kid ourselves by pretending that the only use for suppressors is saving our hearing", the same can be said of cars, knives, bats, bathtubs, scissors, blunt objects like hammers, plastic bags, ....
I still haven't seen you say what problems suppressors cause. If they make a gun less loud, is that a problem?
Sounds like you're using the same argument the anti's use to ban all guns. The mere existence of a suppressor is bad because someone might use it to hurt someone. that explains why there are no gun murders in the US now. People are afraid the sound will give them away.
And, as I mentioned, there are alternatives to commercially available suppressors that don't require a really long wait for an NFA tax stamp to legally own one. Empty a 2-liter soda bottle and tape it to the barrel. From what I've seen, it's not a bad alternative.