report (someone) to the authorities

Translations
сообщить о (ком-то) властям
She threatened to report him to the authorities if he didn't stop harassing her.
Она пригрозила сообщить о нем властям, если он не прекратит ее преследовать.
Definitions
To inform or notify official organizations or individuals, such as law enforcement or regulatory bodies, about someone's actions or behavior that may be illegal, harmful, or in violation of rules or regulations.