A 16-year-old boy 'fist bumped' another teenager before beating a 'paedophile' to death with a bottle and 'cricket ball sizes' rocks, a court heard.
The boy was on holiday on the Isle of Sheppey, Kent, with a 16-year-old girl and a boy, aged 15, when they were approached by Alexander Cashford, 49, at an amusement arcade in August last year.
Mr Cashford gave the girl his number, hinted about his romantic intentions and the promise of alcohol.
The teenagers then sent him messages, using the fake name 'Sienna', arranging to meet him by the sea wall two days later on August 10.
The 16-year-old boy then followed Mr Cashford for 850 metres while he walked on the in Leysdown-on-Sea seafront with the schoolgirl.
He was filmed by his friend catching up with Mr Cashford and striking him across the back of the head with an empty glass bottle.
The 16-year-old boy was also seen by a witness hurling rocks at Mr Cashford's head on the beach.
Mr Cashford was later found dead with multiple injuries.
The 16-year-old admits manslaughter but denies murder. The other boy and the girl deny murder and manslaughter.
The 16-year-old boy has admitted he was going to ambush Mr Cashford for 'trying to get' with the girl and was 'showing off' to his friends.
Jurors were again shown shocking mobile phone footage recorded by the 16-year-old girl of the teenagers attacking Mr Cashford on the seafront.
He is seen being struck on the head with an empty glass bottle by the 16-year-old boy after he sneaks up on him from behind.
Filming the incident, the 16-year-old girl can be heard screaming: 'I'm fg 16, you fg paedophile', 'fg pedo,' 'get him,' fg nonce.'
The 16-year-old then continues to chase after Mr Cashford causing him to trip over.
The 15-year-old boy also trips over before Mr Cashford regains his balance and continues running towards the beach with the older male teenager in pursuit.
Jurors have heard the girl 'wanted to expose Mr Cashford as a paedophile...and wanted to film any beating he got'.
Assisted by an intermediary, the 16-year-old was asked by Kate Blumgart, KC, prosecuting, if the other boy 'wanted to be part of the plan', to which he replied 'yes'.
Ms Blumgart added: 'Did you think you were both going to hit him?'
He answered: 'Yes'
Ms Blumgart asked if he remembered 'fist bumping' with his male co-defendant.
'Yes,' he replied.
She added: 'Because you were going to attack Mr Cashford?', to which he replied 'yes'.
Ms Blumgart asked: 'The girl wasn't part of that attack. She was going to meet him?'
He replied: 'Yes.'
The boy agreed they all thought it was a 'good idea' to move away from the crowds on the promenade before they attacked Mr Cashford.
Ms Blumgart asked: 'Did you think you were going to chase him?'
He said: 'I'm not sure what was going through my head. I saw the bottle and picked it up.'
The boy told jurors he thought it would just cause a 'bump' to the Mr Cashord's head.
The prosecutor asked him: 'Did you want to hurt him? Did you think the bottle on his head would cause serious injury?'
The boy replied: 'No.'
Ms Blumgart asked: 'Why did you try to hit him a second time?', to which he said: 'That was just what was happening.'
Ms Blumgart asked: 'Was it because you wanted to hurt him really badly?'
He replied: 'No. I wasn't really sure what I was thinking. The plan was just for me hit him.'
She said the other boy also 'just hit him.'
Ms Blumgart asked if the girl was 'shocked and surprised' when he hit him.
'No,' he replied.
She asked: 'Why did you try to hit him again a second time?'
The boy replied: 'That's just what was happening.'
Asked why he then threw the bottle at Mr Cashford he replied: 'Because he was too far to hit him with it.'
He agreed he might have thrown a 'cricket ball sized rock' at Mr Cashford as he chased him but not while he was on the ground.
Ms Blumgart asked: 'Did you or did you not throw a rock at him while he was on the floor?'
He replied: 'I'm really not sure. I do not remember.'
The 16-year-old boy added that he may have 'kicked him in the ribs with medium force' but not 'with everything I had.'
The court heard he later shared footage of the attack with three people, with the caption: 'fd pedo up lol'.
The 15-year-old boy and 16-year-old girl both deny murder and manslaughter.
The 16-year-old boy admits manslaughter but denies murder.