In a way that can be detected.

The (relative) effectiveness of a detector

plural of detectivity

Alternative form of detectability

Any agent hired by a private party for the purpose of investigation or evidence gathering.

plural of private detective

Alternative spelling of house detective

A person employed by a privately owned establishment, such as a hotel or large retail store, with the job of preventing wrongdoing and apprehending violators of laws or other regulations.

(Canada, US, derogatory) A forestry official charged with measuring waste in logging operations.

(idiomatic) investigative research