I think they announced their investigation at the same time(the investigation lasted 4-5years). The reason both UEFA and PL were able to launch one was that the email leaks were of public interest. They need a valid reason to launch an investigation. They had one with the hacking scandal and maybe with the failing FFP and the Stanley Park business. They didn't and they wouldn't no matter what excuse they've found to justify it. They would never go after the big sly 3.
To quote the scousers and Carragher: "Why would they be worried about that, let them have unlimited access to the clubs accounts, confidential data, emails and such and see what else they can find(fishing expedition). I yer innocent you shouldn't be worried. ;)" Isn't that one of the most stupid and naive arguments they trot out btw?