is it possible to report someone on here for off site conduct?

to put this in the most succinct way possible, i can say with certainty that a user on here is a groomer & pedophile notorious in a community i am a part of. if i provide adequate evidence for this claim to the relevant parties, would it be possible for me to file a report on this individual, even if their actions didn't take place on this website in particular? if so, how would i go about doing that? thank you!