A more thorough explanation:

Definition: Modus Operandi is a Latin phrase that means "mode of operating." In criminal law, it refers to a distinctive method of operation or pattern of criminal behavior that is so unique that separate crimes or wrongful conduct are recognized as the work of the same person.

For example, if a bank is robbed and the perpetrator wears a purple cowboy hat, carries a gold gun with mother of pearl handles, hums the tune to "Twinkle Twinkle Little Star," and puts the money in a black Gucci bag, and then a year later, another bank is robbed with the same distinctive characteristics, it is likely that the same person committed both crimes. This is because the modus operandi is so specific that it uniquely identifies the perpetrator in both cases.

Modus operandi is used as a basis for admitting evidence of other crimes and is permitted by Rule 404(b)(2) of the Federal Rules of Evidence. This means that evidence of a defendant's prior crimes can be used to prove identity through modus operandi in the current case.

Overall, modus operandi is an important concept in criminal law that helps to identify and prosecute repeat offenders.