What are words for "whistleblower" or "informant"?

You said:

"What are words for "whistleblower" or
"informant"? For example, "We owe it to a small group of brave whistle-blowers
that we know about the infractions at all." or "When with due circumspection
Napoleon was informed that Moscow was empty, he looked angrily at his informant,
turned away, and silently continued to walk to and fro."

Mandaly says:

We say rapòtè, akizatè, denonsyatè, espyon

Haitian Creole ↔ English Reference, Look up Haitian Creole and English Words