There is evidence to back them all. 

The problem with having so many pieces of evidence and so many theories is that people can too easily get thrown off track, going on wild goose chases. It's too much to follow through consistently, and this allows the perpetrators to hide their deeds. 

For such situations, we can take recourse to Occam's razor: the best explanation is the simplest one that explains the maximum number of facts. This is what I offer here.