Five teenage boys have been arrested on suspicion of murder after a 52-year-old Irishman was stabbed to death.
The youngsters, all believed to be aged between 13 and 14, are being held in custody at a north London police station.
Residents in Enfield expressed their grief and shock at the incident.
The victim has been named locally as Jack Barry, who was originally from Cobh in Co Cork and had been living in the UK for more than two years.
It is understood he worked in the construction industry.
The man's girlfriend, Sabrina Finn (35), who is also Irish, is employed by the local council.
She was being comforted by neighbours when she was told her boyfriend had died from his injuries.
Mr Barry, who was described as a "lovely man", is believed to have been involved in a verbal altercation with a group of boys in their mid-teens as he attempted to gain entry into a block of flats.
Police believe the teenagers were attempting to get into a party in another part of the building when they had a disagreement with the victim on Sunday.
The man - who was with a woman belived to be his partner - continued into the block but was followed by two of the boys.
He was then stabbed.
Police and London's air ambulance attended and pronounced the man dead at the scene at 8.37pm.
The entrance to the flats was cordoned off and forensic teams were investigating the surrounding area.
The man is believed to have lived on the second floor of the building with his partner.
One resident of the sixth floor believes he knew the victim, whom he described as Irish.
He said: "If it is the guy I think it is, he was a lovely guy. He was really hard-working.
"He was a construction worker. I talk to him all the time. He's a good guy.
"His partner is a street cleaner for the council.
"By the way she walks, she has some sort of disability."
Police said they believe they know the identity of the victim, but have yet to complete a formal identification and inquiries are still under way to inform all next-of-kin.