Several teenagers were stabbed when a fight broke out at a joint 18th birthday party in Stopsley on Friday.
Gatecrashers attended the party and at about 11.30pm disorder broke out resulting in several people requiring hospital treatment.
One man was stabbed in the leg, another was stabbed in the back, a third was cut on his arm and a fourth was cut in the face.
Most of the party-goers were aged between 17 and 22 and none of the injuries are believed to be life-threatening.
Det Insp Sean Quinn said: “This appears to be an isolated incident which involved a number of people who gate- crashed the party.
“We know there were lots of people at the party who have yet to speak with officers and I would encourage them to do so now. They can speak with officers, in complete confidence, but we need to piece together exactly what caused this disorder and identify the person who was carrying a knife.”
An invitation posted on Twitter before the event said: “If you want to fight get out of the building... If [we] don’t know you, don’t bother coming.”
The hostess later posted: “i dont know how many times i have to stress that people we dont know and people that are in high school still are NOT coming tonight” (sic).
Later in the night, party-goers expressed their disbelief at what had happened.
One guest said: “We should have been posting pics of how good the party was not calling an ambulance NO MORE STABBING just have a chilled event” and “why does this always happen”
The hostess said: “just to confirm, neither myself or [other host] are to blame for last night. It was not compulsory to come”.
Everyone who was treated for injuries has now been released from hospital.
Det Insp Quinn said: “Many of those injured left the scene and went to hospital for treatment before officers arrived – I would be interested in speaking to anyone else who was injured during the disorder or anyone who can help identify those involved.”
Anyone with information relating to this investigation can contact the officer in charge of the inquiry, Det Con Raikes, in confidence, at Luton Police Station, on 01582 394338, or Bedfordshire Police on 101, or text information to 07786 200011.
Alternatively you can contact the independent crime fighting charity Crimestoppers, anonymously, on 0800 555 111.