He is using the same buyer account to send multiple drop-shipments via FBA of the same item and then returning with "Item was not received by estimated delivery date." Amazon is returning them to inventory. One of his drop shipments was actually fulfilled with one of his returns.
I don't get it. I could see doing this to drop ship with 2-day shipping with no cost, but not at the premium that these are going for on Amazon FBA. Maybe trying to launder stolen goods?