A 26-year-old man launched a frenzied attack on his policewoman wife before turning the same blade on himself, an inquest heard.

But the couple's families may never know what turned Richard Mace into a killer before taking his own life.

PC Clare Mace, 23, was stabbed repeatedly in the chest and suffered wounds to her head and neck during the fatal attack on Christmas Eve.

A pathologist revealed that some of the stab wounds had carried such force that they had gone through bone. Richard Mace then went upstairs to the bathroom, leaving a trail of his wife's blood behind, and slashed his own throat and arms with the same knife. He bled to death.

The inquest heard that notes had been left by Richard Mace, an immigration worker, but the contents were not revealed.

Deputy coroner Carolyn Singleton said the only people who would be able to answer the question why the tragedy had occurred were Mr and Mrs Mace.

"This is a tragic case of two young people who had their whole lives ahead of them," she added, recording a verdict of unlawful killing on Mrs Mace and suicide on her husband.

Home office pathologist John Rutherford said his examination of Mrs Mace had revealed stab wounds to her head and neck and more than eight stab wounds to her torso.

There were also wounds to her arms, hands and fingers some of which he described as defence wounds.

Dr Rutherford revealed that one chest wound had gone through the breast bone, through the heart and into the back bone.

Another, from the rear, had come through the 10th rib, penetrated the lung and then penetrated the front ribs. He said the wounds suggested a violent struggle and that bruising to Mrs Mace's neck suggested an attempt at manual strangulation.

He said Mr Mace's wounds were self inflicted and included at least seven separate incised wounds across the throat.

Earlier the couple's next-door neighbour, Miss Susan Metcalfe, of Sefton Close, Clayton-le-Moors, told how on the evening of December 23 she had heard banging coming from next-door and then had heard Clare scream.

She had gone next door and knocked on the door but there was no answer. She again called at the couple's house the following morning and, after discussing the situation with a work colleague, called the police.

She said Mr and Mrs Mace had moved into their house in June 2002 and described them as good neighbours who kept themselves very much to themselves.

Police sergeant Alan Nichol told how he broke a rear window to get into the house and then discovered the body of Mrs Mace in a corner of the living room.

He left the house to radio for back-up and the upstairs of the house was not searched until Detective Superintendent Mick Gradwell went in and found Mr Mace's body in the bathroom.