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.