捜査官

1. Origins, structure, and basic meaning

• Structure: 捜査官, read そうさかん, means an investigator responsible for a criminal investigation.
• Basic usage: It refers to someone who examines traces at a scene or interviews witnesses.

2. Common pitfalls and similar expressions

• The activity and the person
  • 捜査 is the investigation, while 捜査官 is the person carrying it out.
• Source of information
  • In the example 目撃者から, から marks the person supplying the information to the investigator.