CCTV footage captured the moment Kayden Moy’s killers ran away from the scene of the crime, appearing to congratulate each other.
At the earlier trial, jurors were shown video footage from Irvine, North Ayrshire, on the day 16-year-old Kayden was fatally injured.
One clip shows the trio running back through the town after the attack, with Jay Stewart and Cole Turley apparently shaking hands as they did so.
In his sentencing remarks, Judge Lord Scott said they had appeared to “celebrate” the crime.
On Tuesday, the three teenagers guilty of Kayden’s murder were sentenced at the High Court in Glasgow.
Jay Stewart, 19; Cole Turley, 18; and a 15-year-old boy who cannot be named for legal reasons, acted together to carry out the attack at Irvine beach on May 17.
Some of the video evidence from the trial was later released by the Crown Office.
One clip shows the three teenagers in sand dunes at Irvine beach after the attack.
Stewart can be seen bare-chested and holding a cosh – a small, handheld, blunt weapon.
He appears to shout at crowds on the dunes as Turley runs to him.
In another clip, the trio can be seen in an East Kilbride stairwell following the attack.
A still image released by the Crown Office and Procurator Fiscal Service (COPFS) shows the accused walking away from the crime scene after the attack that killed Kayden.
The footage has been revealed after the three teenagers were sentenced on Tuesday.
Turley admitted the killing, while Stewart and the 15-year-old were found guilty of murder last month following a trial at the High Court in Glasgow.
