How to say "investigator" in Japanese

• 探偵たんていCommon
  nounThe everyday word for a detective or sleuth: a private investigator who looks into matters for clients. Also the common word for detectives in fiction.
  彼女かのじょは彼かれを探偵たんていだと言いった。↗

  She described him as a detective.
• 探究者たんきゅうしゃ
  nounAn investigator in the sense of a seeker after truth or knowledge, close to 'researcher'. It points to devoted intellectual inquiry, not to official or criminal casework.
  私はそれに引き付ひきつけられて、それを採用さいようし、ぶっきらぼうな反対はんたいや真正面ましょうめんからの議論ぎろんを止とめ、謙遜けんそんな探究たんきゅう者しゃ、懐疑かいぎ主義者しゅぎしゃを装よそおった。↗

  I was charmed with it, adopted it, dropped my abrupt contradiction and positive argumentation, and put on the humble inquirer and doubter.
• 調査員ちょうさいん
  nounAn investigator in the general sense of a person assigned to conduct an investigation or examination, typically as a member of a team or organization. Fits fact-finding and survey work.
• 捜査員そうさいん
  nounAn investigator in the criminal-justice sense: a member of a criminal investigation, such as police investigative staff. Use it when 'investigator' means someone investigating a crime, which is its usual application.
  捜査員そうさいんらは暗殺あんさつ計画けいかくを摘発てきはつしました。↗

  Investigators uncovered an assassination plot.
• 取調官とりしらべかん
  nounReally an interrogator: an official who questions a suspect. It is seldom the word you want for 'investigator' unless the sense is specifically interrogation of a suspect.

Choose 探偵 for a private detective or sleuth, 探究者 for a researcher seeking truth, 調査員 for a member of a general investigation, 捜査員 for criminal-case investigators, and 取調官 for an interrogator.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 探偵たんていdetective
• 探究者たんきゅうしゃinvestigator
• 調査員ちょうさいんinvestigator
• 捜査員そうさいんinvestigator (usu. of criminal cases)
• 取調官とりしらべかんinvestigator
• 審問官しんもんかんinvestigator
• 調査官ちょうさかんexaminer
• 吟味役ぎんみやくauditor (Edo period)
• 捜査官そうさかん(police) investigator