| detective(noun, person, plant, investigate, agent) |
| analyst(noun, person, search, agent, first) |
| examiner(noun, person, search, agent, first) |
| inquisitor(noun, person, investigate, ask, agent) |
| researcher(noun, person, investigate, ask, agent) |
| gumshoe(noun, person, slang, investigate, agent) |
| explorer(noun, person, search, first) |
| sleuth(noun, person, plant, investigate, agent) |
| dick(noun, slang, investigate, gumshoe, detective) |
| tec |
| inspector(noun, person, inquiry, examiner) |
| inquirer(noun, person, investigate, ask, agent) |
| police detective(noun, expression, idiom) |
| private detective(noun, expression, idiom, person, agent) |
| questioner(noun, person, investigate, ask, tester) |
| research worker(noun, expression, idiom, scientist) |
| eye(noun, informal, investigate) |
| Hawkshaw |
| private eye(noun, expression, idiom, person, gumshoe) |
| spy(noun, person, plant, agent, shadow) |