Re: Either that or
It might be a bluff or not. There's so many variables here including the seller or even "friends" of the buyer that either copped a plea or were undercover. They might have been watching a couple of doggy sites an sorting out where the buyer was.
I don't know about Australia but here in the States, the cops have to be prepared to disclose exactly where and how they gathered evidence so the Bitcoin transaction might have to be explained if it was tracked. Same for the dark web.
The end result at this point is that a lot of drug dealers and buyers will looking over their shoulder ans sweating blood if they try using the web for their drugs.