As someone who has been on the receiving end of federal seizure orders for cryptocurrency private keys, they were in my case satisfied by publishing a transfer (signature) to a USG address, not actual disclosure of private key material, despite that being explicitly stated in the order.

It's not an either/or thing though, right? IMHO, it seems plausible for the FBI to get a private key from a cooperating exchange?

To the previous poster's point: it didn't say which private key. There can be multiple with cloud storage.

From the press release, the scare quotes could mean anything, but they likely had the rough equivalent part:

for which the FBI has the “private key,” or the rough equivalent of a password needed to access assets accessible from the specific Bitcoin address.

Did the crackers surrendered the private keys? And if so why was a warrant issued?

https://www.elliptic.co/hs-fs/hubfs/Screenshot%202021-06-07%...