Teen stabbed to death in attack 'filmed on Snapchat' - but no one has been convicted over his killing

 A mum whose teenage son was stabbed to death in an attack believed to have been filmed on  Snapchat has spoken of her grief over no one being convicted of his killing.

Mohamed Dura-Ray, known as Mo, was killed during a violent street struggle, the day before his mother's birthday, an inquest was told.

But prosecutors were later forced to drop charges against the 16-year-old's alleged killer after a key witness refused to give evidence, Southwark Coroner's Court heard.

After the coroner returned a conclusion of unlawful killing today, Mo's mother Marima Baby Kamara said the family remained devastated by his death in September 2015.

She said Mo's friends told her the attack was filmed on Snapchat, a social network that allows friends to share pictures and videos which are then deleted automatically once they have been watched - and appealed to anyone with information to come forward.She continued: "They (the killers) were doing it on Snapchat. The people said they saw in Snapchat - that is how they knew they had killed him."

The mother added that her son had been on the way to a friend's house when the attack took place, and before leaving had told her "when I'm coming home, I'm going to buy you flowers for your birthday".

Ms Kamara, originally from Sierra Leone, said: "I'm heartbroken. I cry every day, I'm depressed, I can't go to work."

Metropolitan Police Detective Sergeant Cary Crawley told the court that Mo had been seen crying out in pain by witnesses to the attack in the Newington Estate in Kennington, south London, less than a mile from his home in Walworth.He said that at 10pm on Monday, September 14, 2015, witnesses had reported seeing "an unknown male swinging his right arm up and over at Mo", who then called out: "I've been stabbed, I've been stabbed!"

Members of the public gave first aid before paramedics and the London Air Ambulance arrived, Mr Crawley said, but Mo was pronounced dead at the scene at 10.52pm.

A post mortem later showed that he died from a single stab wound to the heart, the inquest heard.

A number of knives were recovered, but none which were later linked to the attack, Mr Crawley said, and detectives also found a letter containing the name of the former suspect, which had traces of Mo's blood.he suspect was later charged on suspicion of murder, but the Crown Prosecution Service was forced to drop the case due to a lack of evidence when another witness refused to testify against him, the policeman added.

During today's inquest, Assistant Coroner Henrietta Hill QC read a statement from Ms Kamara, a former care assistant, in which she spoke of her son's "promising future" as an engineering student.

The family had been preparing to celebrate her birthday together the following evening, and he had made her a birthday hat that read: "I love Mum."

Ms Kamara, in the statement, said: "He wanted to become an engineer. This was his dream."He was my little star. He used to sit next to me at night asking me if I was okay.

"I loved him dearly and he loved me."

She added: "He always helped old ladies to carry their shopping to their front door."

Speaking outside the inquest, Mo's uncle Mohammad Bangura described his nephew as a "brilliant young man", who cared for his mother and younger sister dearly."His mother still asks why," he said.

Mr Bangura said the family was thankful to the police for their efforts, but called upon anyone with information to share it with detectives.

"It has happened to us, but what will happen tomorrow?" he said.