Greater Manchester Chief Constable Sir Peter Fahy has laid flowers at the scene where Pcs Nicola Hughes and Fiona Bone were murdered.
Sir Peter stood in silence alongside colleagues, their heads bowed, a growing pile of bouquets in front of them.
Clearly moved, the chief constable then paid further tributes to the constables, who he described as "two wonderful
human beings, two very dedicated officers".
He said he had spoken to both their families earlier today and recounted some of the kindnesses they had shown to victims of crime.
And he said the families were grateful for the "massive show of public support".
He said: "The two families are just overwhelmed by the huge support they are getting right across the country."
Pc Hughes, 23, and Pc Bone, 32, were killed in a gun and grenade attack in Hattersley, Tameside, on Tuesday morning.
Fugitive Dale Cregan, 29, was detained after walking into a nearby police station shortly after the attack.
Sir Peter said officers were in discussion with the Crown Prosecution Service about charges, adding that he expected that there would be developments in the next 24 hours.
A warrant of further detention was obtained last night for Cregan which will expire at 9am tomorrow.
A 28-year-old man who was arrested yesterday in the Hattersley area on suspicion of conspiracy to commit murder also remains in police custody.
Earlier today, assistant chief constable Garry Shewan said of the criminal feud which preceded Tuesday's murders: "This has to end."
Mr Shewan added: "I think what we've seen on Tuesday has had to appeal to everyone in terms of a watershed moment.
"I would say the strong message that Greater Manchester Police has been using over the last six weeks, and perhaps even further back, is, 'Enough is enough. This has to end'.
"That's why we've been working with individuals with threats-to-life notices as part of our investigation.
"That's why we've had such an intensive policing operation in place.
"And that's why Tuesday's events have hit us so hard."
He went on: "We were investigating a feud between two criminal families, we continue to do that, and the link between that and Tuesday's events is still part of an ongoing and active investigation."
His comments came as a 22-year-old man was arrested after a Facebook page was set up lauding suspected police double killer Cregan as a "legend".
As tens of thousands of tributes poured in from across the nation for the fallen officers, more than one Facebook page was set up in praise of the suspect.
One was titled Dale Cregan OBE, with internet trolls posting messages claiming the alleged killer was a "hero".
Speaking to reporters at force headquarters, Mr Shewan said some people had chosen to use social media in a "very malicious and offensive way".
"I think anybody who perhaps wishes to take the opportunity, following such a tragedy, to tastelessly add derogatory comments, to perhaps think that they're poking fun at such a tragic situation, will always cause a great deal of emotion," he said.
"I think police officers - not just police officers, ordinary members of the public - and I looked at some of these websites and saw ordinary members of the public alarmed and really distressed at some of the ridiculous comments that have been put on there.
"I think they would have wanted us to take positive action and that's exactly what ourselves and Merseyside Police have done."
The 22-year-old man, from Netherley, Merseyside, was arrested last night on suspicion of committing an offence under the Communications Act 2003, he said.
The arrest comes after senior officers thanked the public and said the police took heart from the huge outpouring of goodwill and public support.
The force has received 33,500 messages on its online book of condolence, more than 21,000 have been posted on the force's Facebook page and more than 1.3 million people have viewed the tribute to the officers on Facebook.
It "has meant a great deal to Greater Manchester Police, to its officers, and to all of the partners and also to the communities", Mr Shewan said.
"I know the families too have been taking real solace from reading the positive stories and the positive message of support being expressed by ordinary members of the public here in Greater Manchester and across the UK."
Police officers from across the country have also offered to provide cover so officers from the Greater Manchester force can attend the funerals of the two officers, he added.
After laying flowers in tribute, the Chief Constable, speaking from the Hattersley estate, said: "It's certainly very impactive (sic) just driving up here this afternoon.
"I was very conscious that on Tuesday our two officers, Fiona and Nicola, would have driven up here in the same way attending to a burglary, doing their duty, and sadly they met their deaths.
"Today I have been with the families of both officers."
Sir Peter went on to speak of the dedication of his fallen officers.
"Fiona's family talked about someone who loved camping and actually started a competition on her shift - who could have the biggest tent," he said.
"They talked about how Fiona went to a particular incident involving an elderly lady who had suffered a crime and Fiona went back off duty with flowers and visited the woman a number of times to make sure she was all right.
"Clare, Fiona's partner, was there, obviously very upset, talking about how they had been planning for a civil partnership and how they were looking forward to life together.
"I've also been with Nicola's family today. They talked about somebody who loved karate. Although she was very small in stature, she was a real fighter.
"Indeed, on her shift, if there was a big fence to be climbed or whatever, she tended to be the one who was picked up and thrown over the fence.
"On one occasion they were trying to get into a house and she actually got in through the dog flap because she was so small.
"Again, she actually dealt with an elderly gentleman who had been the subject of a fraud.
"She went back off duty to visit the elderly man again to help him with his paperwork and visited him again on a number of occasions.
"They also talked about an incident when she was driving the police van and came across two cats in the middle of the road and she stopped and actually found there was a mouse there as well. She rescued the mouse, took it down the road to some open ground and then let it go.
"So, two wonderful human beings, two very dedicated officers and two very very proud families obviously devastated by their loss."
Sir Peter said the families had asked him to pass on their "huge appreciation" for the massive show of public support.
"This is a huge comfort to them at a very very difficult time."
He added that he expects the police to charge Cregan in the next 24 hours.
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PA | Posted: 20/09/2012 18:32 Updated: 20/09/2012 18:32