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Principle of “Cui Bono” in Crime Investigation!

March 30th, 2021 cui bono crime investigation

What is “Cui Bono”?

Cui bono is a Latin phrase that means, “who benefits?”.

Cui bono is often used as a mechanism to work out who committed a crime or to establish who is likely to be involved in a crime. Those who stand to benefit from a crime being committed, the logic goes, are the ones most likely to have committed the crime.

The principle of cui bono has been used for thousands of years. The origin of the term is in question, though it does appear in a speech delivered by Marcus Tullius Cicero (known as “Cicero”), who quoted the Roman consul, Lucius Cassius Longinus Ravilla, who – it appears – was fond of using the phrase:

The illustrious Lucius Cassius, whom the Roman people considered the wisest and most conscientious of judges, was in the habit of asking repeatedly in trials, ‘who had profited by it’ [‘cui bono fuisset’]. Such is the way of the world: no man attempts to commit a crime without the hope of profit.”

Though cui bono is a useful and edifying means to establish the most likely suspects, it – as we learn later – only serves as one tool in the investigator’s arsenal. That said, it remains a useful tool that has many real-world applications, some of which we explore below.

Applications of Cui Bono

Police officers and investigators routinely apply the principle of cui bono.

We have all heard of examples, for instance, where a family member died whose substantial inheritance was set to pass onto a named beneficiary. That named beneficiary has every reason, or motive, to commit that crime – or to be a party to it – and so naturally falls into suspicion with investigators. Of course, this does not mean that the named beneficiary must be involved, but that they have a personal stake in the question. Given that money is invariably the source of many crimes, it is unsurprising that the question of cui bono arises in these cases.

Of course, cui bono applies to many other contexts, too, and not just murder. For example, companies can deliberately inject misinformation via the media, not because the misinformation has any direct impact on consumers but that it influences consumers to act indirectly against other companies or to influence consumer behavior in some targeted way. By releasing this misinformation, we can ask the question and learn about the potential financial reasons how the impact of this misinformation benefits the company – either in the short or the long term.

Cui bono also applies to legislation, too. By asking the question, we can establish which companies are likely to benefit from this legislation. We can also learn more about which companies are financially backing legislators to impose this legislation, and why. Rather than considering the legislator as an independent spokesperson for the legislation, as someone who is acting to improve the lives of his/her constituents, we can apply this principle – zoom out and view the bigger picture; of who is behind the legislation and how they seek to benefit from it. We can also establish lines of investigation which hitherto we did not consider.

Drawbacks of Cui Bono

Always remember that cui bono is a form of inductive reasoning. It does not seek to conclusively establish who committed a crime. This contrasts with deductive reasoning which brings evidence together to establish who committed a given crime.

As we have learned, cui bono should not be used as a tool on its own. It does not serve to replace circumstantial evidence – such as DNA or other evidence gathered at the scene of a crime or elsewhere throughout an investigative process. Instead, cui bono can be used to weave together a reasonable basis for assuming who is most likely to have committed the crime; those who have the greatest motive and those who seek to benefit as a direct consequence of the crime.

Of course, the principle of cui bono can be harnessed by criminals, too. It is not uncommon, for example, for criminals to deliberately create circumstances in which a third party is framed to look as if they committed it. This is known as scapegoating. Attention is deflected from those who committed the crime toward some third party who is seen as the prime beneficiary. This is smart on the part of the criminal, and the investigator must be cognisant of this strategy when attempting to unpack a crime.

It is also possible for someone to commit a crime that, rather than actively benefit the accused, actually ends up hurting them. In these cases, there is no obvious benefit for that person to commit the crime. Think, for instance, of cases where a suspect lashes out and murders their partner in a fit of rage.

Take Home Message

The principle of cui bono is important.

It forms the basis of many reasonable and sound judgments by police officers and investigators as they attempt to unpack a crime.

Of course, as we have established, there are many advantages and disadvantages of the principle that must be considered; and that cui bono should never be used alone but, instead, as one tool within the wider arsenal of weapons that investigators can deploy to figure out who was responsible for a crime, why they committed it, and how – by committing the crime – it sought to benefit the perpetrators.

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