This video shows the moment a teenage boy was stabbed to death in an attack that lasted just 22 seconds.

Azaan Kaleem was killed by a group of strangers after first being stabbed in the heart. The distressing footage shows the 18-year-old collapsing to the floor as his killers walk way.

The stabbing was caught on CCTV and Azaan's mother wants the video to be watched by as many people as possible to stop it from happening again.

Azaan, who was known as AJ, was walking down the street with his girlfriend when four men attacked him after hunting him down "like a pack of animals" following a disagreement.

(Image: Bedfordshire Police)

He wasn't part of a gang and had never been in trouble with the police.

The footage was shown on BBC1's Stabbed: Britain's Knife Crime Crisis on Friday night, Essex Live reports.

It told viewers that the attack was down to "nothing more than a chance look between AJ and another teenager".

AJ, wearing a grey Puffa jacket, is first stabbed in the heart. He shows no resistance or aggression as he's hit up to 20 times before sinking to the floor, following the attack in Luton in April last year.

He died three days later in hospital.

Returning to the scene of his murder, his mum Roseann Taylor said: "It was mayhem. There was police everywhere.

"There was a helicopter flying and I could just see people around him.

"The helicopter paramedics came down and they just kept working on him and working on him. I didn't know if it was serious, not serious. Nobody would tell me anything.

"I went to see him as they wheeled him into theatre and he was grey and he was cold and he was wet and I kissed him, told him I loved him. Told him I would see him soon and the next time I saw him was in intensive care. He was brain dead."

(Image: BBC)

Roseann was told to "round everyone up to say goodbye".

"What should have been a private moment, there was no control. There was no...what a mother should normally do.

"Even switching off his machine was witnessed by the police.

"People could hear outside the curtains. It was just...there was no dignity.

"No mum should have to stroke their child's head and kiss them goodbye and wait for their heartbeat to stop.

"It should never happen and this is why I want to share what I'm sharing because it should never of happened."

(Image: BBC) (Image: Bedfordshire Police)

Police were able to track down and charge AJ's killers quickly because of the CCTV.

Two men aged 18 and 19, who can't be named, were given life sentences after being convicted of murder.

Harrison Searle, 18, was also convicted of murder and sentenced to 16 years in jail.

Reece Bliss-McGrath, 20, was found guilty of manslaughter and sentenced to 11 years.

Roseann is fundraising for the Luton and Dunstable Hospital Charitable fund. You can donate here