Cui bono

"Cui bono?" (/kwiː ˈboʊnoʊ/), literally "for whose benefit?", is a Latin phrase which is still in use as a key forensic question in legal and police investigation: finding out who has a motive for a crime. It is an adage that is used either to suggest a hidden motive or to indicate that the party responsible for something may not be who it appears at first to be.

Usage

The phrase is a double dative construction. It is also rendered as "cui prodest?" ("whom does it profit?").

Commonly the phrase is used to suggest that the person or people guilty of committing a crime may be found among those who have something to gain, chiefly with an eye toward financial gain. The party which benefits may not always be obvious or may have successfully diverted attention to a scapegoat, for example.

Background

The Roman orator and statesman Marcus Tullius Cicero, in his speech Pro Roscio Amerino, section 84, attributed the expression "cui bono" to the Roman consul and censor Lucius Cassius Longinus Ravilla:

L. Cassius ille quem populus Romanus verissimum et sapientissimum iudicem putabat identidem in causis quaerere solebat "cui bono fuisset".

The famous Lucius Cassius, whom the Roman people used to regard as a very honest and wise judge, was in the habit of asking, time and again, "To whose benefit?"

Note the usage of the longer form "cui bono fuisset" ("To whose benefit?" or "For whose advantage?").

Another example of Cicero using "cui bono" is in his defence of Milo, in the Pro Milone, once again invoking Cassius as the source: "Let that maxim of Cassius apply."

American sociologist Peter Blau has used the concept of "cui bono" to differentiate organizations by whom has primarily benefited: owners; members; specific others; or the general society.

See also

• Brocard (law)
• Cherchez la femme
• Follow the money

General:

• List of legal Latin terms
• List of Latin phrases