Civilians who are used to obtain facts and intelligence about criminal activity and/or participate in it so evidence can be obtained for an arrest are called:

• A. Snitch
• B. Informants
• C. Tattlers
• D. Witness

Answer: (B)

The main idea here is the formal role of informants in law enforcement. Informants are civilians who are used to obtain facts and intelligence about criminal activity, and they may even participate in wrongdoing to help gather evidence for an arrest. This term is the standard, professional label for such individuals. Slang like snitch or tattler is informal and pejorative, not the proper legal term, while a witness is someone who observes events and provides testimony—not someone recruited to gather evidence or participate in crimes to obtain that evidence. So, informants best fit the description.