There has to be some probable cause. Trump can't just demand investigations. He shouldn't have the authority for it, but we've not been in a situation like this before. It doesn't seem illegal for him to do this but even if it were, the only people that can stop him are in congress and they won't.
That's another conspiracy theory dude. I think we've talked about this before but it becomes religious at some point. I don't believe in god and I don't believe in conspiracy theories.