Company informer

• One who exposes wrongdoing
• Employee who calls out bad practices, say
• Person with inside information making public some illicit activity
• One discloses having broken elbow in Canadian ski resort
• Wrongdoer's bane

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
also whistle-blower , 1963 in the figurative sense, American English, from whistle (n.) as something sounded in an alert + agent noun from blow (v.1).

Wiktionary Word definitions in Wiktionary
n. (alternative form of whistle-blower English)

Wikipedia Word definitions in Wikipedia
A whistleblower ( whistle-blower or whistle blower ) is a person who exposes any kind of information or activity that is deemed illegal, unethical , or not correct within an organization that is either private or public. The information of alleged wrongdoing ...