Bait money or bait bills are used by banks to aid the tracing of bank robbers.
Bait bills are bills whose serial number is recorded by the bank either by making a copy or by listing in a log book. During a bank robbery if robber has taken the bait money, details of this can be passed on to the police. If the money is found in the possession of someone or used to purchase goods then it is often easier to find the perpetrator of the bank robbery. [1]. When the bait money has left the bank it is known as hot money.
It is also the title of a book by author Max Allan Collins.