Investigation (noun)

1. The systematic examination of a matter in order to discover the facts.
2. An inquiry into a crime or other matter to establish the facts.

Origin:

Late middle english: from old french, or from latin investigatio(n-), from investigare "track down" (see investigate).

Examples:

1. The police are conducting an investigation into the robbery.
2. The investigation revealed that the company was engaging in illegal practices.
3. She conducted a thorough investigation of the matter.
4. The investigation was closed due to lack of evidence.
5. The investigation team has been working on the case for weeks.