The mother of murdered 12-year-old Ava White today branded the teenager who killed her in a petty row over Snapchat video a 'monster' after he posted a selfie on the same platform from behind bars.

Harry Gilbertson - who was 14 when he fatally stabbed Ava - was unmasked by Mail Online today as he turns 18.

Ava's campaigning mother Leeann, who has dedicated her life to tackling knife crime, said it was 'important the public know who he is' now that he is legally an adult.

To her fury, despite the fact that he's currently serving a minimum 13-year sentence for murdering Ava in November 2021, muscle-bound Gilbertson managed to upload an image of himself onto Snapchat.

For her family it was particular hurtful because the argument which led to Gilbertson stabbing the schoolgirl in the neck was sparked by his refusal to delete a Snapchat video he had made of Ava and her friends.