If you want to rob a bunch of ATMs and get away with it, try keeping your vulnerable window longer than 2 hours...
I mean, it's going to be pretty straightforward to gather a bunch of footage and see what happened those 2 hours. These guys will get busted within the next few days basically guaranteed.
Besides, I think the decision to execute the transactions in a short time window is correct. Otherwise banks would easily spot a pattern in the transactions (max amount, stolen CC, South Africa) and start rejecting them. Even if legitimate transactions are denied, it's still worth it. They would have never been able to get away with $12 mil in cash.
A small crew can disappear but 100's of people at least some of them with records and known to the police not a chance.
Dead drops? One guy talks, they have a drop site. Law enforcement knows how to do stakeouts. Wait until someone comes to pick up the cash from the drop site, tail him to wherever he goes next.
Deposit it in real banks and transfer it somewhere? Okay, now you don't even need a participant to cooperate, you can just identify him and pull his bank records.
Maybe they convert it to BTC. Are there mixing services doing enough volume to really be untraceable? Otherwise investigators can watch it on the other side and see whose bank account it gets converted into.
Of course, if they pulled this off effectively, the drops all were probably executed soon after the 2h window, and then you've got a much colder trail to follow, even if you find one of the mules and magically have video surveillance of the region.
And then you have a 100-player Prisoner's Dilemma, unless they organized the group in a decentralized manner.
Cash flows up, risk flows down. Seems to be the MO of most organized crime.
These 100 guys aren't a part of "the group" though, they're just random idiots hoping to score a quick buck.
The people actually running this in all likelihood aren't even in japan.
His friends says, "What are you doing? You can't outrun a bear!"
His friend replies, "I don't have to outrun the bear; I only have to outrun you!"
How can you really find someone from 100x100 pixel image? I am genuinely interested.
Chances are the ones going to the ATMs are money mules (https://en.m.wikipedia.org/wiki/Money_mule), probably not of the completely innocent kind, but of the "not too smart, falling for a 'want to earn $100 in an hour?'" question from a 'friend'.
$100 will give them about a 10% cut, if they do one ATM. It is more likely, though, that they had each guy do >1 ATM. So, you would need, maybe, around 250 of these guys. To recruit them, find around 50 slightly smarter but still not too smart guys who get $2000 each. On top of that, you need real criminals who can make sure the lower levels do not run away with the money, either by convincingly threatening them with bodily harm, or by following them to the ATMs while staying out of view of the cameras.
Yes, costs will add up, but you should be able to keep costs below 50%.
Plus, we probably wouldn't be hearing about it a week after the fact, if it's part of a long-standing interaction like the yakuza, barring someone with loose lips.
As if those 100 guys matter...
Please tell me how you'd do it instead? Build robots to go to the ATMs?
Only thing that matters here is the link between the people going to the ATMs and the people actually running the operation.