THIS is the Greater Manchester police officer brutally stabbed to death in an anti-terrorist operation.

Forty-year-old Special Branch detective constable Stephen Oake died as three suspects of North African origin were arrested yesterday afternoon at a flat in Crumpsall, north Manchester.

Four other police officers were injured during a raid linked to last week's discovery of the deadly poison ricin in London,

DC Oake was a family man, a father of three, and a committed Christian and churchgoer.

His devastated family, wife of 20 years Lesley, aged 40, his son, aged 15 and two daughters, aged 14 and 12, were today believed to be at their home in the village of Poynton, Cheshire, just outside Stockport.

Today, as the three suspects, aged 23, 27 and 29, were being interviewed, key questions remained unanswered:

Why was DC Oake's killer not handcuffed?

How was the killer able to launch an attack with a large kitchen knife more than an hour after the initial police raid on the flat?

Why was DC Oake not wearing body armour?

He died at North Manchester General Hospital after receiving emergency treatment at the scene.

He and the other officers were attacked after one of the suspects, aged 27, broke free .

Three of the officers attacked, including DC Oake, were from Special Branch and were not wearing protective clothing, Greater Manchester Chief Constable Michael Todd said.

Uniform officers who had initially gone into the flat were wearing protective clothing.

Mr Todd said the Special Branch officers had gone into the flat to collect intelligence after the arrests had been made at 4.22pm and would not have expected to be confronted by a man with a knife.

"There were no armed officers involved in the operation whatsoever," he said.

Mr Todd confirmed today that the attacker was not handcuffed at any stage.

He said the suspects were detained and actually being held by officers at the time.

"So it was then decided that

you can't handcuff someone while you are actually conducting that sort of examination," he said.

"One of the individuals was being held by a police officer, a uniformed officer who was protected, and it appears from the debrief that we have done overnight, that the suspect has managed to break free from the officer, the two of them have then literally, in fighting, gone into the kitchen area, where the suspect has managed to grab hold of a knife.

"I have to say then the Special Branch officers, including Steve, very bravely went to assist their colleagues and that's how he has been fatally stabbed."

Commenting on the fact that the Special Branch officers were not wearing body armour, Mr Todd added: There was no perceived risk."

DC Oake is thought to be the first policeman killed in a mainland anti-terrorist operation for more than 10 years.