If you suspect someone in your movement of being a long term undercover cop or an informant you either keep that shit to yourself until you know more or you spend the energy to do the research needed to confirm or deny your suspicions.

You do not under any circumstances create a whisper train of rumours, silently drop someone out of your social circle or otherwise isolate someone based on a suspicion.

Imagine if someone did that to you on a hunch. That shit destroys communities and creates paranoia. It’s long term impact is almost as bad as having an undercover or informant around. Do not do it.