“FBI officials said on a Monday call with reporters, though, that encryption has been a challenge, including foreign-based encrypted email accounts. The FBI said there has been no indication of foreign involvement with Crooks' plot, but investigators have hit delays getting into those accounts.”
Looks like they are going to try for a universal back door to break all encryption again.
https://www.foxnews.com/us/trump-assassination-attempt-fbi-still-does-not-have-complete-access-shooters-online-activity