blow the whistle on sb/sth

/blˈəʊ ðə wˈɪsəl ˌɒn ˌɛsbˈiː slˈaʃ ˌɛstˌiːˈeɪtʃ/

/blˈoʊ ðə wˈɪsəl ˌɑːn ˌɛsbˈiː slˈæʃ ˌɛstˌiːˈeɪtʃ/

to blow the whistle on sb/sth

to inform the authorities about something secret or the breach of legalities, particularly because one is morally obliged to do so

Examples

1. This group of Rockford residents worked for years to blow the whistle on contamination left behind from Wolverine's old tannery.

2. This group of Rockford residents worked for years to blow the whistle on contamination left behind from Wolverine's old tannery.

3. [Narrator] Later that year, Litvinenko and a handful of colleagues took the extraordinary step of blowing the whistle on state corruption at a press conference in Moscow.

4. [Narrator] Later that year, Litvinenko and a handful of colleagues took the extraordinary step of blowing the whistle on state corruption at a press conference in Moscow.