The 15-year-old was detained on suspicion of assisting an offender after PC Fiona Bone, 32, and PC Nicola Hughes, 23, were killed in Mottram on September 18.
Dale Cregan, 29, has been charged with the murders, along with the murders of two other men.
Assistant Chief Constable Steve Heywood said: "We remain committed to fully investigating the circumstances surrounding the murders of PC Fiona Bone and PC Nicola Hughes - We continue to ask the public to search their conscience and urge anyone who has any information to contact us."
The officers' funerals will take place next week.




