A teenage boy has been arrested on suspicion of murder after a 15-year-old aspiring musician was found stabbed to death in east London.
Tashaun Aird was knifed in Somerford Grove in Hackney on the evening of Wednesday, May 1.
Scotland Yard said a 16-year-old boy was arrested on Thursday morning and taken into custody at a north-west London police station.
It comes as Romain Williams-Reid, 18, of Erith Crescent, Romford, was charged with Tashaun's murder, and grievous bodily harm with intent in relation to a second victim.
Detectives believe the youngster was killed after a "fracas" with a group of youths in a park.
Tashaun was found at the scene suffering from stab injuries and died at 9.49pm.
A post-mortem examination gave the provisional cause of death as a stab wound to the lung.
The Met's homicide and major crime command are investigating the incident, in which another 16-year-old was also stabbed in Somerford Grove.
His injuries are not life-threatening and he has now been released from hospital.
Detective Chief Inspector Helen Rance, leading the investigation, said: "Our investigation is making good progress and my officers are following a number of lines of inquiry, but we know there is more work for us to do in tracking down all of those involved in this horrific murder of a teenage boy who had his whole life in front of him.
"We know that witnesses saw Tashaun and the 16-year-old victim being attacked by a group of youths in a park near Somerford Grove.
"Tashaun was part of a group of about six when four suspects ran at them. We retain an open mind as to any motive behind this terrible incident.
"It would have been quite a scene and following the confrontation everyone fled.
"If you haven't spoken to police about what you saw, I need you to get in touch.
"If you are worried about telling police, or even if you don't want to speak to us directly, I would urge you to use anonymous methods such as Crimestoppers where you could provide vital information without even having to give your name.
"The people who killed Tashaun and seriously injured another 16-year-old boy must be removed from the community, and only you can help us do it."
In a statement released through police on Friday, his family said: "Tashaun was family-orientated, he loved his family and we loved him dearly.
"He was passionate about his music and he loved drawing.
"He was a loving, caring boy with an infectious laugh."
