I don't know if I know a troll, as most of them are anonymous, and suspicions or rumours cannot be trusted.
There are too many fake news and half-truths, which are distorting facts and events.
And real evidence is not easy to find or might lead to erroneous judgements, all the more if you see how many users are misinformed or have been fooled.
https://en.wikipedia.org/wiki/Internet_troll