Officers investigating the murder of a man on a bus exactly one week ago will be revisiting the scene in an appeal for information.
Mr Whelan tried to stop his attacker from escaping despite his injuries
Richard Whelan, 28, of Kentish Town, north London, was stabbed up to six times after asking his attacker to stop throwing chips.
Police will be handing out leaflets in Upper Street, Islington, and in Holloway Road.
A Met spokeswoman said it was vital for all witnesses to come forward.
Mr Whelan and his girlfriend boarded the number 43 bus in Islington at about 2145 BST and made their way on to the top-deck.
His attacker, described as black, in his 20s, just under 6ft tall with afro hair and wearing a dark jacket and a hooded top with the hood up, got on at the same stop.
The man then began throwing food forcing all the passengers, but Mr Whelan and his girlfriend, to move to the lower deck.
After enduring this behaviour for 15 minutes, and when the abuse turned to his girlfriend, Mr Whelan stood up to the man.
Police said he was then stabbed up to six times as his girlfriend tried to pull the attacker off.
Despite his injuries, Mr Whelan then attempted to stop the man getting away, before collapsing on the bottom deck of the bus.
The attacker got off the bus at Holloway Road near the junction with Wedmore Street and walked away.
Det Ch Insp John Macdonald said "Mr Whelan did absolutely nothing wrong whatsoever.
"This was a totally unprovoked attack by someone who obviously carries a knife as a matter of course."
Mr Whelan's girlfriend is expected to be interviewed by officers in the next few days.