Why is he being investigateed now and not during the hundreds of other times he was involved in drama?
This isn't a 'investigate' like anything in a conventional sense, he probably left his facebook or other social media public and overreacted to disgruntled idiots searching for his personal detail and regurgitating public knowledge to strike fear.
Why it's happening now is because Tony's pushed too much against the grain with his shtick. That's pretty much all there is to say.