V n to n
III.9 The 'betray' group
These verbs are concerned with telling people in authority that someone has done something wrong. The prepositional phrase indicates who the authority is. The implication is usually that the person referred to by the Subject betrays the other person by giving this information.
The unnamed protagonist of the drama is a student on the run from his own revolutionary comrades, having betrayed them to the police under torture.
My parents didn't talk to me because I grassed him up to the police.
In the case of turn in, the noun group following the verb is often a reflexive pronoun. This pattern is V pron-refl P to n.
betray denounce report shop grass up turn in
We're reminded of those late-night movies in which the anguished serial killer turns himself in to police and says, 'Stop me before I kill again.'