A 16-year-old boy has been arrested on suspicion of murder after two teenagers were stabbed to death at a house party.
The teenager, from Milton Keynes, is the fourth person to be detained in connection with the deaths at a birthday party in Archford Croft in the town on 19 October.
Dom Ansah, 17, died from a stab wound to the back and Ben Gillham-Rice, also 17, was knifed in the chest.
Two men have been charged with two counts of murder.
Charlie Chandler, 21, of Fitzwilliam Street, Bletchley, and Earl Bevans, 22, of no fixed abode, have also been charged with two counts of attempted murder in relation to two males who were seriously injured in the incident.
A 27-year-old was arrested on suspicion of conspiracy to murder and released under investigation.