The FBI/DOJ has always had access to all of the emails, and was simply not interested in doing a serious investigation. Had they been, a Grand Jury would have been impaneled to investigate this issue 14 or 15 months ago. The fact that DOJ never permitted a GJ was the Big Tell, but there are so many procedural irregularities in the original "investigation" that it's pointless to claim that a particular mail protocol is now a game changer.
What changed here is that agencies outside of the Clinton Cartel have seen the emails, forcing the FBI to at least pretend to take a second look. My guess is they will try to destroy all of these records as well.
The problem here is twofold.
One, the NYPD had Anthony Weiner's laptop for the sexting of underaged girls. And if there's anything a cop doesn't like, it's kitty pr0n or similar. So they'd have had their best forensic guys going after it. And you KNOW when they saw what was on it, they made copies.
Two, speaking of copies. If Anthony Weiner was sexing teenage girls, he was surfing pr0n. If he was surfing pr0n, his computer was infected. If his computer was infected, lotsa shady people got those emails.
In other words, it's gone from "Got any naked pictures of the Secretary of State's closest advisor? Wanna buy some?" to "Hey, China, Russia, North Korea, ...got any Top Secret and abover info from the Secretary of State? Wanna buy some? (and if you act now, some prime blackmail material for the likely next President?"
Gawd these people are fornicatingly stupid.