I do not believe this is true, ongoing investigations in most cases come with a gag order that prohibits Google from disclosing an user is being investigated.
Like it was in Null's case for example, he learned about it years after the subpoena
https://kiwifarms.st/threads/2024-0...account-grand-jury-subpoena-from-2022.192870/
You also give feds too much credit for being so fast with their actions, the shooting was just a few days ago. Even if it was the case, hinting one of the suspects to them investigating wouldn't be beneficial to the case.
I may be wrong, but this timing just seems too good. I believe he is doing this for attention,