Police have named two teenage boys who were stabbed to death in Milton Keynes late on Saturday evening.
Thames Valley Police say Ben Gillham-Rice, who was 17, died of a stab wound to the chest.
A second boy, also 17-years-old, has been formally identified as Dom Ansah.
A Home Office post-mortem, which took place on Wednesday, established his cause of death as a stab wound to the back.
Two other males, a 17-year-old boy and a 23-year-old man, also suffered injuries as a result of the incident and are recovering, police said.
A 21-year-old man from Milton Keynes has been arrested on two counts of murder and two counts of attempted murder.
He remains in police custody.
Police confirmed the families of the victims are being supported by officers and urged anyone with information to "do the right thing" by coming forward.
Detective Chief Superintendent Ian Hunter, Head of Crime for Thames Valley Police, said: "We are still seeking others in connection with this dreadful incident, and would again appeal to anybody who has any information that can assist our investigation to make contact with police.
"If there is anybody that has information, but has not yet contacted us, I ask you to look into your conscience and come forward."
He added: "Do the right thing and hand yourselves in to your nearest police station."