Let's say this guy has just come into about $1,000,000 and didn't win any Boy Scout badges getting it. What does he do with it?
He can't keep it in his house, because if the cops get a search warrant against him, a duffel bag filled with cash under the bed can be embarassing.
He could put it into a safe deposit box, but he'd either have to visit it too often, which would suspiciously show up on the bank's records, or visit it
infrequently, which means carrying huge sums of currency around. In either case, if the police want to look at the box, the bank has to let them.
A checking account? By law, deposits of more than $10,000 have to be reported to the Treasury Department. If our friend just deposited $9,000 at a time, he would have to make over 30 transactions, another flag in the air for the authorities to see.
This guy can't win, can he? When you deal with banks, you leave tracks. You could spend a few thousand a year and attract no attention, but who wants to live on 5 digits a year when you've got 7 digits laying around? Dirty money
must be LAUNDERED in order for it to truly become your cash. The methods for doing this vary depending on certain circumstances.