The teenager who murdered Ava White told a police officer "shut up you nonce" when he was being questioned about the killing in an interview.
Ava, 12, was stabbed in the neck by a boy, 14, in a row over him filming her on Snapchat.
A trial heard how Boy A, who cannot be named for legal reasons, smirked and and laughed after the incident, then ran away and dumped his flick knife, designer jacket and mobile phone in a "cover up".
