Dye pack


A dye pack is a radio-controlled incendiary device used by banks to foil a bank robbery by causing stolen cash to be permanently marked with dye shortly after a robbery. They were invented in Georgia, United States, in 1965. In most cases, a dye pack is placed in a hollowed-out space within a stack of banknotes, usually $10 or $20 bills. This stack of bills looks and feels identical to a real one, but usually subtly marked in a way that is only privy to selected bank employees. The development of flexible dye packs makes it virtually impossible to detect by persons handling the stack.
When the marked stack of bills is not used, it is stored next to a magnetic plate near a bank cashier, in standby or safe mode, ready to be handed over to a bank robber by a bank employee. When it is removed from the magnetic plate, the pack is armed. Once it leaves the building and passes through the door frame, a radio transmitter located at the door triggers a timer, after which the dye pack explosively releases an aerosol and sometimes tear gas, intended to destroy the stolen money and mark the robber's body with a bright stain. The chemical reaction causing the explosion of the pack and the release of the dye creates high temperatures of about which further discourages a criminal from touching the pack or removing it from the bag or getaway vehicle.
Dye packs are used to foil robberies in over 75% of banks in the U.S.
In England, a robber who fled a bank in Regent Street laughing "Haha, I've got all the money", was enveloped in "a red cloud" of dye as he ran away down Shaftesbury Avenue. He was later caught and jailed.