Yep, you're spot on - although in this case, as I recall, the market did return (from memory it was nightmare market or 'Sinaloa' market (perhaps a different cartel name)), but there had been some kind of canary device activated via a signed PGP message from the admin.

It wasn't long before the admin released a subsequent signed message claiming that it was a false alarm with some excuse as to what had happened, but it was clear that the operation was, from that point on, a honey pot.