The search for a killer who stabbed a passenger to death on the top deck of a London bus four days ago is continuing.
Mr Whelan was the victim of an unprovoked attack, say police
Richard Whelan, 28, was killed by a man who had been throwing chips at his girlfriend on the 43 bus at about 2200 BST on Friday.
Officers have been speaking to people living in the Holloway Road area and are now going through CCTV footage.
They also want to hear from a potential witness who was on the top deck.
All the other passengers moved downstairs when the man started throwing food after getting on the bus in Upper Street, Islington.
Mr Whelan put up with it for about 15 minutes, but got up to ask the man to stop when he started harassing his girlfriend.
He was stabbed up to six times as his girlfriend tried to pull the attacker off and died an hour later. His killer got off the bus at Holloway Road after the attack.
Det Ch Insp John Macdonald said Mr Whelan had done nothing wrong and was the victim of a "totally unprovoked attack".
On Monday it emerged Mr Whelan, who lived in Kentish Town, was a friend of one of the victims of the 7 July bombings.
He helped in the search for fellow Arsenal supporter Ciaran Cassidy, 22, who was killed in the explosion on a Piccadilly Line train near King's Cross station.
Mr Cassidy's mother Veronica said: "They were good friends and Richard was a fairly quiet lad, not the sort to get into any trouble.
"Richard was a real support and what has happened to him is tragic, especially after everything else".
Mr Whelan's attacker is described as black, in his 20s, just under 6ft tall with afro hair and wore a dark jacket and a hooded top with the hood up.