A 20-year-old man has been arrested on suspicion of murder after a 16-year-old boy was stabbed in Pimlico, central London.
Hani Hicham Abou El-Kheir died after he was stabbed "multiple times" by a gang of teenagers in Lupus Street, Pimlico on 27 January. He was taken to a south London hospital but later died of his injuries.
Police have now arrested a 20-year-old man in connection with the incident following early morning raids across London.
Police believe at least 10 youths were involved in the attack and have appealed for more witnesses to come forward to help with the investigation.
They have also asked parents who believe their child was involved in the murder to persuade them to come forward.
Det chief Insp Neil Attewell, of the Homicide and Serious Crime Command [HSCC], said: "The tragic events of last Sunday have left Hani's mother and wider family completely devastated.
"Hani's mother has lost her only child and is still coming to terms with the heartbreaking events that have led to the death of her son.
"I am directly appealing to the parents and carers of those believed to be involved - if you have slightest indication that your child may have been involved in this incident I encourage you to get them to hand themselves into the police. Failing to do so will result in my officers pursuing them until we have caught all those responsible.
"Likewise there will be a number of young people who will have information about the course of events that day. Parents, we urge you to encourage your children to come and speak to us. We understand that some might have some concerns with speaking to the police but it is important that they do so and we can offer reassurance and support for those that can assist us with our enquiries.
"Hani suffered a horrific and sustained vicious attack and as we continue to actively seek those involved. I am giving those who were there a chance to hand themselves in now before we come looking for you, we will relentlessly pursue to the nth degree all those we believe to be involved that day.
Any witnesses or anyone with any information should contact the incident room on 0208 345 3715; if you wish to remain anonymous call Crimestoppers on 0800 555 111.