捜査員

1. Origins, structure, and basic meaning

• Structure: Written 捜査員 and read そうさいん, it denotes a person assigned to investigate a case and gather facts or evidence.
• Basic usage: It is used for someone checking security footage or interviewing residents at a scene.

2. Common pitfalls and similar expressions

• Person rather than institution
  • It names an individual carrying out investigative work, not the investigation itself or the agency as a whole.