A 45-year-old woman has this morning (Wednesday) been arrested for assisting an offender in connection with the murders of Milton Keynes teenagers Ben Gillham-Rice and Dom Ansah.
The woman is aged 45 and lives in Milton Keynes, say police.
This is the ninth arrest officers have made in connection with the double murder.
Ben and Dom, both 17, died of stab wounds following a house party in Archford Croft in Emerson Valley on Saturday October 19.
Two other males were injured during the same incident.
Five people have already each been charged with two counts of murder and two counts of attempted murder.
They are Charlie Chandler, aged 21, of Fitzwilliam Street, Bletchley, Earl Bevans, aged 22, of no fixed abode, Clayton Barker, aged 19, of Surrey Road, Bletchley, and a 15-year-old boy and a 16-year-old boy - neither of whom can be named for legal reasons.
All five have been remanded in custody to appear at Luton Crown Court on Monday 27 January 2020.
A 27-year-old man from Milton Keynes was arreste earlier this month on suspicion of conspiracy to murder, while 53-year-old man and a 40-year-old woman, both from MK, were arrested on November 14 on suspicion of assisting an offender. These have also have been released under investigation.