A man was beaten to death by a gang of thugs after confronting a thief who stole his girlfriend's Halloween hat.
Ben Gardner, 30, suffered fatal head injuries after he was punched and kicked to the ground in Sutton, south London, in the early hours of Sunday morning.
The former bank worker was returning from a Halloween night out with his girlfriend, who was wearing a black fancy dress witch's hat.
As the couple walked down Throwley Way, one member of a drunken group of men and women grabbed the hat and walked off.
It is believed that when Mr Gardner asked for it back, the thief spat in it before handing it over.
At this point several other members of the group attacked Mr Gardner, leaving him unconscious in the street with fatal injuries.
His girlfriend was also punched and suffered minor injuries.
Paramedics were called and took Mr Gardner to a south London hospital where he died yesterday evening.
A Metropolitan Police spokesman said five men and two women were being questioned today at several south London police stations.
An eighth man who was arrested in the early hours of Sunday morning has been released and will face no further action.
Detectives from the Metropolitan Police's homicide and serious crime command, led by Detective Inspector Bob Campany, are responsible for the inquiry.
Mr Campany said: "Although it was 3.30am there were a lot of people in the area at the time of the incident as the local clubs were closing.
"We would like any information from witnesses who may have been on Throwley Way at the time.
"This appears to be a violent unprovoked attack on an innocent man who was out enjoying Halloween night with his girlfriend."
It is believed that Mr Gardner worked for a branch of Union Credit Bank in Sutton which has since closed.
Anyone with information is asked to call the incident room at Sutton 0208 721 4005 or Crimestoppers on 0800 555 111.