I like to keep an open mind on these things. I don't know if you have a case or not, but it's interesting.
As you say, there may be more radical factions within AIM, similar to the Provo faction of the IRA. Revolutionary movements often--in fact almost always--produce such radical fringe groups.
In that case, it puts a new light on AIM's recent repudiation of Ward Churchill. It could be that they're simply telling the truth, and they want to rid themselves of an embarassment. Or it could be that he has had some sort of covert connection with AIM and now they are publicly repudiating that.
Churchill has a very big connection with the Denver- Boulder AIM. Nothing covert at all.
Other AIM groups don't like him.