A 22-year-old man killed in a double stabbing outside a Tesco store in Kilburn, north-west London, has been named by police as Sven Badzak.
Detectives said Mr Badzak was chased by a group of males and was attacked after falling on Willesden Lane.
Mr Badzak's 16-year-old friend was also stabbed in the attack and remains critically ill in hospital, the Met Police said.
Ch Insp Guy Ellwood described the attack as "barbaric".
Officers were called to Willesden Lane at 17:40 GMT on Saturday where they found Mr Badzak injured.
Mr Badzak was taken to a hospital in central London where he later died, Det Ch Insp Darren Jones said.
He added: "At this early stage we believe Sven and his friend became involved in an altercation with a group of males.
"As this group chased the pair, Sven and his friend became separated. Sven fell to the ground and was attacked by a number of the group.
"His friend was also attacked but managed to seek sanctuary in a shop. However, he remains critically ill in hospital."