Mr Cregan, 29, denied the murders of Greater Manchester Police constables Fiona Bone (pictured left) and Nicola Hughes (right) at Liverpool crown court this morning.
The unarmed officers died after responding to a report of a burglary in Hattersley, Greater Manchester, on September 18. Relatives of the two officers were in the court to hear Mr Cregan plead not guilty to their murders, and the murders of a father and son earlier in the year.
Mr Cregan appeared in the court via videolink alongside nine co-defendants, the majority of whom are charged with the murders of either David or Mark Short in May and August 2012.
Cregan denied the murders of the officers as well as seven other charges, including the murders Mark and David Short. He is also charged with four counts of attempted murder and one of causing an explosion.
Luke Livesey, 27, from Hattersley, and Damien Gorman, 37, from Glossop, pleaded not guilty to the murder of Mark Short and three counts of attempted murder.
Anthony Wilkinson, 33, from Beswick, denied the murder of David Short, possession of a firearm with intent to endanger life, attempted murder and causing an explosion with a hand-grenade.
Jermaine Ward, 24, denied the murder of David Short, one count of attempted murder and an allegation of causing an explosion with a hand-grenade.
They were remanded in custody until their trial at Preston Crown Court on 4 February.
The remaining defendants, Matthew James, Ryan Hadfield, Leon Atkinson, Francis Dixon and Mohammed Ali, were not asked to enter their pleas at today’s hearing.
James, 33, of Clayton; Hadfield, 28, from Ashton-under-Lyne; and Atkinson, 34, of Newton-le-Willows, are charged with the murder of Mark Short and three counts of attempted murder.
Dixon, 37, from the Stalybridge area, is charged with the murder of David Short, attempted murder and causing an explosion. Ali, 23, from Chadderton, is accused of assisting an offender.
They were remanded in custody to return to Liverpool Crown Court on December 20 to enter their pleas.