A 16-year-old boy has been arrested following the fatal stabbing of a teenager at a railway station in south London.
The suspect, from Balham, is being held in connection with the death of Louis Johnson, 16, at East Croydon station on Monday, British Transport Police said.
Emergency crews, including the air ambulance, were called shortly after 16:45 GMT but Louis died at the scene.
A post-mortem examination is yet to be held.
On Tuesday, Det Chf Insp Sam Blackburn from BTP described the “senseless killing” as “truly devastating”.
In response to the attack, BTP and the Met Police increased their patrols in the East Croydon area and a Section 60 order was enforced on Monday evening.
A Section 60 gives police officers the right to search people within a certain area if they think a person may be carrying a weapon or, in this case, a murder weapon.
London Mayor Sadiq Khan said he was “deeply saddened” by what happened.
“Violent crime destroys lives and devastates communities,” he added.
Following the attack, Croydon Central MP Sarah Jones said: “This brutal loss of a young life is another reminder that tackling violence must be our highest priority at every level of government and across our communities.
“I will not stop campaigning on this until our children are safe on our streets.”