The detective who led the hunt for the killers of Shawn Seesahai said his experienced team were left in shock when two 12-year-old boys were identified as suspects.

A month-long trial, which ended with the boys being convicted of murder on Monday, was told that the youths were arrested 10 minutes apart at their respective homes, 24 hours after 19-year-old Mr Seesahai was pronounced dead.

Jurors at Nottingham Crown Court heard how neither boy summoned any help, opting not to call 999 anonymously, as they left their victim for dead on an area of grass near Wolverhampton’s Stowlawn Primary School.

Speaking after the trial, Detective Inspector Damian Forrest, of West Midlands Police, said the “brutal” joint attack followed a minor disagreement on Stowlawn playing fields.

The officer said: “We received a call from West Midlands Ambulance Service saying that a young man had been attacked and had life-threatening injuries.

“A short time after that we were told he had actually passed away at the scene.

“I was the on-call senior investigating officer for homicide, so I turned out from home and went over and then spent the rest of my night with my team doing the early building blocks of the investigation.

“Later the following day, we had some information which allowed us to identify the two suspects in the case and we learned that they were 12 years old.

“I have been a police officer for 20 years and this isn’t the first time I’ve been out to a young man who has lost his life in a really violent way, but to then find out that two 12-year-olds were responsible was shocking and made us all on the investigation team stop and pause and think about things.

“But I have got a really professional team with lots of experience and we gathered our thoughts, adapted our policies and our processes appropriately, and carried on with the investigation from there.”

The senior investigating officer added: “In my career, I have not come across children as young as 12 carrying and using a machete in the manner which has been described in court.”

Noting that West Midlands Police has initiatives such as the Home Office-backed Operation Guardian to tackle knife crime and youth violence, Mr Forrest warned that young people associating with those carrying knives could be held responsible themselves if weapons were used in a violent incident.

He said: “If you are out in a group and you know that your friend has got a knife and you then use serious violence, you need to know that you can be responsible for that as well.

“It’s very difficult when people are carrying large knives to try and pretend that you don’t know about it when they are pulled out and used in the manner in which they were on Shawn.

“They are both young boys. Neither of them had ever been arrested or dealt with for knife crime-related matters.

“Nor had any of them ever been charged with any other offences.”

The detective added: “I would urge young people and the community to read about this and realise that … no one wins in a situation like this.

“You have got a life of a young man who had everything in front of him, which has now ended. And you have got the lives of two boys which are irrevocably changed.

“I think people who carry knives within the community need to think that there are consequences to those actions – it goes beyond just any sort of notion that you might need to protect yourself or that it might give you some sort of status or respect.

“There are very real consequences and these consequences change and end lives.”

Asked about the nature of the killing, the senior officer continued: “The attack was a brutal attack on a young man who was just over with his friends in Wolverhampton.

“The level of injuries that he sustained ended his life.

“If a knife is used in a fight then there is a very real chance that you are going to cause serious life-altering or life-ending injuries.

“The evidence from the witnesses and the CCTV suggests that this was a minor disagreement between two parties or two groups that didn’t know each other. And there is no reason why they shouldn’t have just walked away and gone their separate ways.

“But knives can change the outcome of these situations. That’s why I would ask everyone to think strongly before taking, carrying or using one.”