A man was beaten to death by a gang after he confronted 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.
He had been on a Halloween night out with his girlfriend, who was wearing a black fancy dress witch's hat, when a man stole it and spat in it.
Five men and two women are being questioned by police over the attack.
An eighth man who was arrested has been released with no further action.
Mr Gardner, a bank worker in Sutton, died in hospital on Sunday evening following the attack in Throwley Way.
His girlfriend was also punched during the attack and suffered minor injuries, police said.
Det Insp Bob 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."
