Two unarmed female police officers were killed in a rare grenade and gun attack with links to organised crime Tuesday in an incident that has reopened the debate on arming the British police.
A 29-year-old man wanted for two previous murders has been arrested in connection with the killings in Tameside, Greater Manchester, northwestern England, after handing himself in at a police station.
British Prime Minister David Cameron paid tribute to the two officers, saying their deaths were a "shocking reminder of the debt we owe to those who put themselves in danger to keep us safe and secure."
Police said suspect Dale Cregan had lured police officers Fiona Bone (32) and Nicola Hughes (23) to their deaths by making a bogus burglary report that they went to check, thinking it was a routine incident.
Greater Manchester Chief Constable Peter Fahy said it was one of the "darkest days" not only in the history of the force but of British policing.
"When they arrived it appears then that Cregan emerged into the road and killed these two officers. A firearm was used and grenade was also used," Greater Manchester Chief Constable Peter Fahy said.
Bone died at the scene, while Hughes died a short time later, police said.
"It would appear Cregan has deliberately done this in an act of cold-blooded murder," Fahy added.
The incident led to fresh calls for the arming of British police, who unlike their counterparts in many countries generally do not carry weapons.
But Fahy said he opposed the idea.
"We are passionate that the British style of policing is routinely unarmed policing," he said.
"Sadly we know the experience in America and other countries that having armed officers certainly does not mean that other police officers do not end up getting shot dead."
Fahy said Cregan had been protected by a "criminal conspiracy" while police were hunting him for the murders of a father and son, David and Mark Short, in separate incidents earlier this year.
David Short, 46, was killed in a gun and grenade attack in August while his 23-year-old son died in a pub shooting in May.
"This case tells us something about the nature of organised crime, the web of intimidation," Fahy said.
Tuesday's shootings sent shock waves around the sprawling Hattersley council housing estate where the tragedy unfolded.
Many residents returned home from work to find police cordons still in place and forensics officers combing the scene.
Local window cleaner Warren Shepherd was working close to where the incident happened.
"I just heard gun shots, bang, bang, bang -- around ten of them, then a pause and a big explosion," he said.
"Everybody was in shock and couldn't believe it," he added.
Murders of police officers are rare in Britain, although an off-duty policeman was shot dead when he confronted a gunman in Essex, east of London, in July.
In another high-profile British case, PC David Rathband was blinded in 2010 when he was shot by fugitive Raoul Moat as he sat in his patrol car in Newcastle, northeast England. He was found dead at his home in February after a suspected suicide.
His son, Ash Rathband, was among those calling for police to be armed after Tuesday's events.
"It's time for police to be armed in my opinion," he said. "Yet again another awful incident."
Asked in parliament if the killings would reopen the debate on arming police, Cameron said: "There are more armed police officers, there are more armed response units. But this was supposed to be the response to a domestic burglary and that wouldn't normally require armed officers."