Investigation

I think it could also include technical investigations. For example, when building envelope defects, a technical investigation is often required in order to determine the cause and to propose corrective measures. But in such specific case, usually, the full term "technical investigations" will be used.

In the business section, it means companies doing investigations, often it's private detective services or any kind of investigations (financial investigations, criminal investigations, private detective services, etc.). 

 

Hope it will help you.