a person whose occupation is to investigate and solve crimes

to conduct a formal criminal investigation or inquiry to gather evidence and facts

to scout or reconnoiter for military or strategic purposes; the act of gathering intelligence

to break into, scout, or analyze communications or technical data for intelligence purposes

to officially file a case and initiate a criminal investigation

An aircraft used for surveillance or gathering military intelligence.

to investigate a crime and prosecute

a soldier or operative sent out to gather information about the enemy or terrain

a person, often in a military context, sent out to gather information about the enemy or terrain

to detect or sense something, often through technical, scientific, or investigative means

to interrogate someone during an investigation

to investigate, track down, and arrest a suspect or criminal

to listen secretly to private conversations or tap phone lines

having an investigatory or reconnaissance nature

detection unit

special investigation team (Taiwan)

economic crime investigation

National Reconnaissance Office (of the United States)