A 15-year-old has been charged with conspiring to murder a schoolboy who was stabbed to death in the street.
Baptista Adjei, also 15, from North Woolwich, was attacked on Stratford Broadway, east London, on 10 October.
Police have charged another 15-year-old boy with murder, GBH and two counts of possessing an offensive weapon.
The latest suspect will appear at Stratford Youth Court later, Scotland Yard said.
A man stabbed to death at a London Underground station was an Arsenal fan on his way to a match, the BBC has been told.
Tashan Daniel, 20, was was killed in an “unprovoked attack” on the platform at Hillingdon station on Tuesday.
He had been heading to the Emirates Stadium to see the Gunners face Nottingham Forest in the third round of the Carabao Cup, a source said.
It is the third murder investigation on the Tube network this year.
No arrests have been made over the attack, which Det Supt Gary Richardson described as “a shocking act of violence”.
He said the British Transport Police (BTP) investigation was in its “early stages”.
“We believe a group of young men were involved in an altercation on the platform before one of the men received a fatal stab wound,” he said.
Police and paramedics were called to the station in west London at 15:57 BST.
An air ambulance was also sent to Hillingdon, but Mr Daniel was pronounced dead at the scene.
Danielle Foster, who was driving past Hillingdon station at the time of the stabbing, said upon “hearing so many sirens, I knew something terrible had happened”.
“Lots of people were being turned away from the station as it had been closed,” she said, adding: “Then the police helicopter began circling the scene.”
Hillingdon station was closed by Transport for London (TfL) while police searched the area.
The station was closed for the rest of Tuesday evening and reopened at 05:45 this morning.
So far in 2019 more than 100 murder investigations have been launched across London by the Metropolitan Police and BTP.
A fourth teenager has been arrested on suspicion of the murder of a boy at a chicken shop in central London.
Josiph Beker, 17, was stabbed to death outside Edgware Road KFC, Westminster, at about 14:00 BST on 10 September.
A 16-year-old boy was arrested on Sunday in connection with the murder. He remains in custody.
Two 16-year-old boys were charged with murder on Saturday. An 18-year-old arrested over the murder has been bailed pending further inquiries.
Three people have been arrested on suspicion of attempted murder after a 15-year-old boy was stabbed.
The victim remains in a critical condition in hospital following the attack in Tottenham, north London, on Friday.
He was found with multiple stab wounds on Willan Road, in the Broadwater Farm estate, at around 11:15 BST.
Scotland Yard said three males were detained in connection with the incident on Friday evening.
Officers believe the boy was involved in an altercation shortly before he was stabbed, possibly by a suspect riding a bicycle.
Police would like to speak to members of the public who gave first aid to the victim at the scene.
Det Insp Paul Ridley said: “I am keen to hear from anyone who either witnessed, or has information concerning this attack.
“The victim, not yet 16 years old, sustained multiple stab wounds and is fighting for his life.
“If you know anything about the circumstances surrounding the incident or if you witnessed it, please do come forward.
“I would also appeal to the members of the public who valiantly administered crucial first aid to the victim to come forward to my investigation team.”
Anyone with information is asked to contact police on 101.
A 16-year-old boy has been stabbed to death in north-west London.
Police officers and the London Ambulance Service were called to Munster Square in Camden at about 23:10 BST on Monday.
Scotland Yard said the victim was pronounced dead at the scene and no arrests have been made.
A murder investigation has been launched and a crime scene remains in place. The Met has urged witnesses to come forward.
A large police cordon stretching across a number of roads was in place on Tuesday morning.
A teenager was stabbed to death in a west London shop as he tried to hide following a fight, witnesses have said.
The victim, believed to be 18, was attacked in Uxbridge Road, Shepherd’s Bush, on Wednesday night.
Local resident Derek Parks said the man had gone into the store “for cover” but he was followed by a man who had a knife and stabbed him.
The Met said officers had attended along with paramedics at about 21:20 BST but the man died at the scene.
Mr Parks said the fight happened “outside the shop doorway and the gentleman came in from outside”.
“The guy who got stabbed went towards the basement of the shop and was hiding,” the 64-year-old said.
Shopkeeper Sully Singh said he had received a call from his night staff at about 21:45 and had found a police cordon in place when he arrived.
“When I came here everyone was shocked. They said an incident had happened. There was a fight,” he said.
Another man suffered non-life-threatening injuries in a stabbing in nearby Notting Hill earlier on Wednesday evening.
The man was stabbed just after 19:00 on St Ann’s Road and police were “neither linking nor ruling out” a connection between both attacks.
No arrests have been made.
One local man, who did not want to be named, told the BBC: “I just told my kids to stay indoors. If you don’t have to go in the road, don’t have no argument with no-one because you don’t know. It could be any one of us.”
Det Insp Luke Wyllie said: “A young man’s life has been tragically cut short.
“Our thoughts are with his friends and family at this very difficult time. We are doing everything we can to apprehend those involved.
“Extra police and specialist units are working on the ground now to build a clearer picture of what took place and work to protect and reassure those in the local community.”
A Section 60 order – which gives police the power to stop and search people in a designated area – has been put in place in Shepherd’s Bush and Notting Hill until Thursday afternoon.
Police are in the process of informing the teenager’s next of kin and a post-mortem examination will be held in due course.