A 16-year-old girl was arrested on charges of murder after a man was stabbed to death in south-east London.
She is the third person to be arrested for the murder of Ayodeji Habeeb Azeez, 22, in Anerley, at lunchtime, Sunday 4 November.
On Friday morning, the girl was arrested at an address south of London, the Metropolitan Police reported.
On Sunday, two men aged 19 and 21 were arrested for suspected homicide and released under investigation.
Investigators believe that Azeez has been attacked by four or five people. A post mortem examination gave its cause of death as a series of stab wounds.
Azeez, from Dagenham, east of London, was one of five stabbing victims in the capital in six days.
DCI Mark Cranwell, who leads Anerley's investigation, has appealed for witnesses. "This attack happened in the middle of the day, in the middle of a residential street, and it goes without saying that this incident would have stood out in what would normally have been a quiet environment," he said.
"It seems that four or five suspects were involved in the attack, and both they and Ayodeji were seen running into Samos Road by Grace Mews." At this point, Ayodeji had been attacked, suspects fled in one direction, while Ayodeji he went to the opposite side before he collapsed.
"We need information from the public to help us keep the momentum of this investigation going forward."
On Monday evening, John Ogunjobi, 16, died in front of his parents at Tulse Hill, in the south of London. His was the violent death in London this year.
The DCI Richard Vandenbergh, who leads the Tulse Hill investigation, said: "We believe that the victim was attacked by a number of suspects and the altercation would undoubtedly attract the attention of those who they were nearby ".
Witnesses are invited to call Crimestoppers on 0800 555 111.
The other three victims were Rocky Djelal, 38, Jay Hughes, 15, and Malcolm Mide-Madariola, 17.
Chief Supt Simon Messinger, commander of the South Central Unit of the Met, said the extra officers were enrolled in the area after the grooms.
"We have recently witnessed a series of fatal stabs in the south of London, with five murders in the last week, a murder is one too many, with the devastation it causes families, friends and communities that are difficult to understand", he said.
"Addressing violence is a priority and one that remains at the forefront of all the work we do, including the use of our local resources, but also integration with resources from across the Met, including task force for violent crime. "