A 28-year-old man arrested on suspicion of conspiracy to commit murder, in relation to the deaths of two police officers, has been released without charge.
"As we have said before, this remains a complex investigation and we are fully investigating the circumstances surrounding the murders of PC Fiona Bone and PC Nicola Hughes.
"We have been touched by the many thousands of messages received from the public who are as shocked as we are and as a force we want to thank them for their support over the last few days.
"I would urge anyone who has any information to assist this investigation to do the right and just thing and contact us."
29-year-old Dale Cregan has been charged with four counts of murder and four counts of attempt murder.
Officers from Greater Manchester were joined by colleagues from other UK forces. Hear what they had to say at PC Nicola Hughes's funeral.
Thousands of police officers from across the UK joined members of the public for the funeral of PC Nicola Hughes in Manchester.
PC Nicola Hughes who was shot dead with her colleague Fiona Bone in Hattersley will be laid to rest today.