A 16-year-old girl has been arrested on suspicion of murder after a 22-year-old man was stabbed in south London.
Two men, aged 19 and 21, had earlier been held over the death of Ayodeji Habeeb Azeez in a residential street in Penge on Sunday.
The pair were released under investigation.
Met Police have said Mr Azeez was killed in the “middle of the day” in what “would normally have been a quiet environment”.
Detective Chief Inspector Mark Cranwell, from the Met’s Homicide and Major Crime Command, said before the attack that it appeared four or five male suspects were in the involved in the attack.
He added: “The suspects fled in one direction while Ayodeji went the other way before he collapsed.
“I am appealing to anyone who was in the area on Sunday afternoon and saw this attack, or the events surrounding the attack, to come forward and speak to police.
“This includes trying to establish if anyone was with Ayodeji when he was attacked.
“My officers are making progress as to why Ayodeji was in the area, why he came to be attacked and who was responsible for his murder, but we need information from the public to assist us in keeping the momentum of this investigation moving forward.”