Not long after Karl Gallagher arrived at West Cross Shopping Centre, in Smethwick, he got into a confrontation with Tyrelle Harris, then aged 19, who ended up fatally stabbing him.
Both men had arrived at the scene in separate cars, and in different groups, on the afternoon of April 26 last year, before words were exchanged and there was an altercation between the pair.
A member of public had recorded the moment Tyrelle Harris, from West Bromwich, fatally plunged the knife into the chest of Mr Gallagher, before the victim quickly fell to the ground and never got back up.
Watch: Moments that led to murder:
With such clear evidence facing Harris, it was highly unlikely he would escape the hands of the law.
During his murder trial, Harris admitted carrying the knife - which he tried to hide down a drain - and also carrying out the stabbing. But he denied intending to kill the personal trainer and instead claimed he was acting in self-defence.
Having heard and seen clear evidence, including CCTV from a nearby business, however, jurors convicted Harris of murder following a deliberation of eight hours and 20 minutes.
Mr Gallagher was pronounced dead at the scene at 5.21pm - around 50 minutes after arriving to buy food from F1 Pizza.
He had pulled up in a Seat Leon as a front seat passenger, along with several friends, while Harris arrived in a black Hyundai with three friends.
A short while later, there was communication between the two groups, which led to the escalation of violence.
Coverage of the case:
Harris's defence counsel, David Mason QC, said Mr Gallagher became aggressive to the defendant's friends, and Harris tried to step in and diffuse the situation.
But jurors were told that this led to Mr Gallagher squaring up to Harris, and saying: "Are you stupid? You know who I am? – I’m going to shoot you in your face."
Harris claimed to have seen Mr Gallagher posing on social media with a firearm previously, and believed he had served a lengthy prison sentence due to firearms, which made him more scared of him.
Fearing a firearm "would be produced", the defendant then stabbed Mr Gallagher, the trial heard.
A post-mortem examination revealed Mr Gallagher died of a single stab wound measuring three-centimetres to his upper chest, which ruptured a main artery.
After the stabbing occurred, Harris and his associates fled the scene on foot and ran across a dual carriageway, leaving his victim for dead.
The defendant dropped the murder weapon, which was a flick-knife, down a drain on nearby Orchid Close, but this was later recovered by police.
Two days after the killing, Harris was arrested at an associate's address on New Road, Netherton, where he was found hiding in an attic. He declined to answer questions in interview.
In the mobile phone footage, Harris was seen wearing a black hoodie and a Gucci man-bag.
He was also seen wearing gloves which he told jurors was because he feared of getting Covid.
"It was Covid time and I was worried about touching public stuff," he said, in cross-examination from his defence counsel, David Mason QC. "I was worried about unhygienic things."
He also told jurors he felt "numb" once he carried out the stabbing, but added: "I didn’t intend to hurt him."
Harris said he found out later that evening Mr Gallagher had died from the mother of a friend.
Following the stabbing that day, police urged people not to share the video footage. That footage played a key role in bringing Harris to justice fairly quickly, said Detective Inspector Adam Jobson of West Midlands Police.
So too did witness accounts, including from a taxi driver who at first believed Harris had pushed Mr Gallagher - until he saw blood.
Mr Jobson said: "This case was captured on CCTV. Not only was it captured by the CCTV fixed to the commercial premises at the location but there was a witness who actually recorded it on his mobile phone.
"So as you can imagine, with people's smartphones in this day and age, the quality was really clear, HD [high definition] quality.
"So that along with witness accounts that we had, enabled us to identify the offending people and those people present fairly quickly, where we were able to locate them and arrest them. That is how we identified those people on that day."
Watch: DI Adam Jobson talks about devastating effects of knife crime:
Asked how hard the investigation had been, he continued: "At the time, we obviously had no idea who the offender was or the people who were with him.
"My team worked tirelessly on it to get the right outcome for the family.
"It has proved difficult because the defendant has gone down the lines of self defence.
"Obviously, the victim is no longer with us to offer his version of events. So that has been the difficult thing to challenge that account and prove beyond reasonable doubt that the offender obviously hasn't acted in self defence and is guilty of murder."
Speaking about Harris being found guilty, he added: "It is obviously brilliant news for the family. They have had to live this nightmare since April when the incident took place.
"It gives them some kind of closure, although they won't be free from what's happened. For the rest of their lives, they will have this suffering around Karl's premature death.
"However it gives them a positive justice outcome which I think is rightly deserved."