Nine people have now been arrested by police who released an updated appeal for information after a man was fatally stabbed in Streatham on Thursday afternoon (June 11).

Six males and three females are in custody at police stations in south London having been arrested on suspicion of "various offences", the Met said Friday.

Police moved quickly to make the arrests after the stabbing, which happened in the vicinity of Prentis Road in Streatham.

The Met Police were called there to reports of a stabbing around 4.15pm on Thursday, and with London Ambulance Service (LAS) paramedics attended to find a male with a stab wound to the chest.

He was taken to a hospital in central London and sadly pronounced dead at 4.51pm, prompting the murder investigation.

Read more: Seven arrests made after teen stabbed to death

Police said they "believe they know the identity of the victim", thought to be in his late teens, and have informed his next of kin.

"Formal identification and a post-mortem examination will follow in due course", a Met spokesperson added.

Meanwhile, Detective Chief Inspector Wayne Jolley, leading the investigation, urged anyone with information about what happened to come forward.

"A dedicated team of officers are working tirelessly to find the people responsible for this attack. I urge anyone with any information to come forward to police. We are aware there are several outstanding witnesses and it is vital we speak to these people to help establish the circumstances around what happened.

"Were you on Prentis Road between 16:10hrs and 16:25hrs? Did you witness an altercation, or see anyone running away?

"I am appealing to people who live within this area who may have private CCTV and drivers with dash cams who were travelling through the area at the time of the incident. You may have captured significant footage that we need to recover as soon as possible.

"I also urge anyone within the community who may have information about this murder to come forward to police. We are keeping an open mind as to the circumstances behind the attack and information given to police will be treated in the strictest confidence.

"Please call police on 101 quoting reference CAD 5897/10June. To remain anonymous, contact Crimestoppers on 0800 555 111," he said.

Streatham MP Bell Ribeiro-Addy said her "thoughts and prayers" were with the family of the victim in a Twitter post.