A murder inquiry has been launched after a man was stabbed to death at the home of former boxing world champion Herbie Hide.
Detectives believe a number of people will have witnessed the attack at the former boxer's house in the village of Bawburgh near Norwich.
The man, believed to be in his twenties, was stabbed just after midnight following an argument.
The victim, who has not been named, was pronounced dead at the scene by paramedics shortly after they arrived.
Detective Superintendent Julian Gregory told Sky News: "We're getting an emerging picture of a dispute and an argument and an altercation between individuals.
"The victim was stabbed in front of a number of people, we're obviously appealing for people who were at the party to get in touch, and perhaps more importantly, to the person who was responsible for the stabbing.
"It happened in front of a number of people, we will get to you, so we would appeal to you to come forward."
Herbie Hide is thought to have left the party before the stabbing.
Detectives are now trying to speak to as many of 300 people who attended the party in order to get a clearer picture of what happened.
A post mortem examination is underway to determine the cause of death. Detectives are also hoping to formally identify the victim overnight.
Norfolk Police have said that while they continue their invesigations at the large house, Herbie Hide and his family are staying elsewhere.
A police spokesman said: "Mr Hide and his family have relocated as police carry out investigations at the scene."
Hide, known as the Dancing Destroyer, has been WBO world heavyweight champion twice but in 2006 stepped down to the cruiserweight division.
The following year he won the WBC International cruiserweight title.
He has not fought since beating Welshman Wayne Brooks in the Crusierweight Prizefighter tournament in April 2010.
Anyone who has information about the incident should contact police on 101 or call Crimestoppers anonymously on 0800 555 111 .