in
( informal ) to take sb to the police or sb in authority because they have committed a crime :
She threatened to turn him in to the police.
He decided to turn himself in.
in
( informal ) to take sb to the police or sb in authority because they have committed a crime :
She threatened to turn him in to the police.
He decided to turn himself in.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005