Two teenagers have been arrested on suspicion of beating an elderly man to death in what police believe was a racist attack.
Akberali Tayabali Mohamedally, 80, was assaulted in the White Hart roundabout subway in Northolt, west London on Friday.
He was found at 1900 BST and taken to hospital where he was pronounced dead.
Two 16-year-old boys were arrested on Sunday on suspicion of murder and are being questioned at two stations.
Mr Mohamedally, who lived in Northolt, west London, was originally from Pakistan.
Detective Superintendent Sue Hill said: "This was a despicable attack on a frail old man by cowardly individuals.
"They assaulted him and left him for dead, and we are treating the incident as a racially-motivated murder."
She said several local people had witnessed the attack and had helped police.
A post-mortem examination will be held to find the exact cause of Mr Mohamedally's death.