Four people have been arrested after a 22-year-old man was stabbed to death on Friday at Middlesex University.
The man, who was not a student at the London university, was thought to have been involved in a fight when he was stabbed.
He was taken to hospital by London Air Ambulance but died soon after arriving. A post-mortem confirmed that the man died of stab wounds to the chest.
Detectives have this morning arrested four people; a 21-year-old woman, two 20-year-old men, and a 21-year-old man, in connection with the incident.
The investigation is being led by officers from the Homicide and Major Crime Command (HMCC) under Detective Chief Inspector Nicola Wall.
DCI Wall said: "We are keen to hear from anyone who witnessed the incident on the university campus near the student union area shortly after 0100hrs on Friday 31 October.
"There was a student event ongoing before this fight took place and many people would have been passing through the area before and after the fatal stabbing."
Anyone with information is urged to contact the incident room on 020 8785 8244 or Crimestoppers anonymously on 0800 555 111."