The videos are alarming in any circumstances.
But when you consider what happened just days after they were filmed in June last year, they become especially chilling.
The clips show Joseph Jeremy brandishing weapons he had ordered off the internet.
In one, the then 17 year-old brandishes a machete-type weapon at the home of his friend, Ethan Strickland.
In another video, Jeremy shows the handle of a 15-inch hunting knife protruding from the waist-band of his tracksuit bottoms. He’s wearing a balaclava.
Both videos were recovered from Joseph Jeremy’s phone.
Just days after they were taken, the knife seen in the video was used to inflict fatal injuries on 26 year old Ryan O’Connor.
Jeremy has been convicted of murder and robbery alongside Lewis Aquilina.
During the trial, the court heard how Jeremy - who admitted to having a “fascination with knives” - and who has previous convictions for possession of an imitation firearm, racially aggravated assault and wounding - travelled to Newport on June 10th last year with 4 other defendants on a “road trip to commit crime.”
Travelling in a stolen Ford Fiesta, they drove through the Alway part of the city looking for people to rob.
When they spotted Ryan O’Connor - a popular character known as ‘Apple’ - they pounced.
Witnesses described two balaclava-clad men rushing from the car and attacking Mr O’Connor on a roundabout.
It was a brief assault, but a fatal one. A pathologist later found five stab injuries including one to the victim’s heart and lungs. The 26 year old father was left to bleed to death at the scene.
The robbers, meanwhile, made off with a Gucci bag and belongings worth £40. Jeremy was said to have told his fellow defendants ‘I yinged him’ (slang for ‘stabbed’).
He was also heard to say “we’ve got his bag.” Eye-witnesses reported hearing laughter from the car as it drove off.
The stolen car was brought off the road about 45 minutes later in Cardiff by police using a ‘stinger’ device to burst the tyres.
Jeremy - whose social media handle is “juice-spiller”, a nickname he said was given to him by a friend serving life for murder - live streamed his arrest using his mobile phone.
Footage of the police pursuit was played to Cardiff Crown Court.
In court, Jeremy claimed he’d stayed in the car throughout the robbery, which he blamed on his co-defendants Lewis Aquilina and Elliott Fiteni.
Mr Fiteni was found not guilty of all charges.
Questioned about the videos found on his phone in the days before the fatal incident, he said he’d just been ‘messing about’ and that there was “no point to them.”
Jeremy - who’s now 18 - was found guilty of murder and robbery following a 2-month trial and Newport Crown Court.
Lewis Aquilina, 20, was found guilty of the same charges.
Kyle Rassis, 18, who like the other defendants are all from Cardiff, was convicted of manslaughter and robbery.
Ethan Strickland, 19, was convicted of robbery.
All five defendants will be sentenced at a later date.