This should be a pretty good rebuttal to those jerkoffs who proclaim bitcoins are only ideal for money laundering etc. I'm sure these guys had heard of bitcoins and I'm sure they would have happily used them. But how the hell do you turn $7M into bitcoins when you're in honduras, and how do you do the reverse in Panama?
At the same time, this also should be seen as a defect in bitcoins. These guys could have been legitimate buyers and/or sellers of some goods and they would have had an equally tough time using bitcoins. Not exactly a great recommendation if the banking system is much easier to use.
OP perhaps you should change the title to "how could these guys have pulled this off using bitcoins?"