Русско-англо-русский юридический словарь

In law, unjust enrichment is where one person is unjustly or by chance enriched at the expense of another, and an obligation to make restitution arises, regardless of liability for wrongdoing. A common example is when a party contracts to provide a service, but the contract is terminated prematurely due to a breach, and the contractor unjustly receives no compensation for partial services rendered.

The concept of unjust enrichment is based upon the Roman legal maxim "no one should be benefited at another's expense" (nemo locupletari potest aliena iactura or nemo locupletari debet cum alien iactura). (Wikipedia)

catch red-handed. Also, catch in the act. Apprehend someone in the course of wrongdoing, as in The boys were trying to steal a car and the police caught them red-handed, or He tried to cheat on the exam, but his teacher walked in and caught him in the act. The first term referred to blood on a murderer's hands and originally signified only that crime. Later it was extended to any offense. The variant ( catch in the act) is a translation of the Latin in flagrante delicto, part of the Roman code and long used in English law. (The American Heritage® Dictionary of Idioms by Christine Ammer)

An administrative proceeding is a non-judicial determination of fault or wrongdoing and may include, in some cases, penalties of various forms. They are typically conducted by government or military institutions. (Wikipedia)

There are two distinct types of legal wrongdoing: civil and criminal. (Cambridge University Press)