Double escrow[1] is a set of real estate transactions involving two contracts of sale for the same property, to two different back-to-back buyers, at the same or two different prices, arranged to close on the same day.
At close of escrow, all participants, lenders, sellers, buyers and brokers are informed of all parties involved and all monies that change hands.
For example, a double escrow might be arranged in which Alpha sells Greenacre to Beta, the sale to close at 10:00 am this morning; and Beta then immediately sells Greenacre to Gamma at 2:00 pm this afternoon.
If the double escrow is undertaken for a criminal purpose, it will not be legal.
In these jurisdictions, double escrow will be completely impossible because the back-to-back sales may not even close during the same week or month, let alone on the same day.