Detectives have named the 21-year-old man who was fatally stabbed in a shopping centre, as a third suspect has been arrested in connection with the killing.
Officers and members of the public carried out first aid, and the London Ambulance Service and the London Air Ambulance were called. Despite their efforts, Mr Ngwendema died at the scene.
Police made two arrests nearby soon afterwards. The first, an 18-year-old man, was arrested on suspicion of murder. The second man, aged 22, was arrested on suspicion of murder and affray. Both remained in custody, the Met Police said.
A third man, aged 20, was arrested on Wednesday at his home in Harrow on suspicion of murder and is also in custody.
Mr Ngwendema’s mother Thethe Elonga told the Evening Standard: “I’m heartbroken. He was a wonderful boy, respectful and lovely. He did very well at school and had a very bright future ahead of him.”
Mr Ngwadema’s uncle Fred said: “He was a very good boy, quiet and polite. He wanted to do businesses studies and then set up his own business one day, selling clothing or food.”
A post-mortem examination found the cause of death to have been a single stab wound.
Detectives, who are appealing for witnesses or anyone with information to come forward, said the area remained a crime scene.
Detective Chief Inspector Linda Bradley, leading the investigation, said: “We are directly appealing for information from anyone who may have witnessed the incident and is able to help us with our investigation. We are especially urging anyone with footage of the incident or the aftermath to get in touch with us immediately.
“There was a significant number of people nearby when this tragic incident happened, and I am confident that there are people out there who are yet to come forward. No matter how insignificant the information may seem to you, please contact the police as soon as possible.
“As you can imagine, Gedeon’s family are experiencing unimaginable grief, and we want to bring answers and justice to them as quickly as we can. This is a complex investigation, and we appreciate the local community’s support and understanding while we continue to conduct our enquiries.”