If they carried out the attack they would have had the private key in their possession.
or by "in possession of the private key" they mean "Coinbase generated the private key earlier and just gave it to the FBI"
the amateur hour doesn't stop there though
Especially together with 'FBI Director Compares Ransomware to 9/11' articles like https://www.foxbusiness.com/technology/fbi-chris-wray-ransom...
You might find it interesting to know that, irl, I never talk about anything remotely conspiratorial. I live life like a normal person, and talk like this on forums as a hedge.