AN ex-police officer who stabbed his estranged wife to death after sending her a series of obsessive threatening letters, has been given a life sentence for the killing.

Glenn Richards plunged the eight-inch blade of a kitchen knife into his wife's heart in front of witnesses, before calmly walking away.

Mrs Karen Richards, who was in the process of divorcing the ex-Metropolitan Police sergeant, died at Watford General Hospital on Monday, May 7, last year, the same day as the attack.

Letters written by Richards found in the kitchen of her home included one promising to give her "a goodbye present", a clear reference to the knife.

Richards had been imprisoned for harassing his wife while serving with the London force. He had breached a series of court injunctions ordering him not to make any contact with her.

The anti-harassment orders were imposed to protect Mrs Richards.

The sergeant had a history of depression, had been sectioned under the Mental Health Act to Watford General's psychiatric ward, and was living in a St Albans care home at the time of the killing.

By this time he had retired from the Met with a pension on medical grounds.

He was considered a sufficient threat by police for them to install a panic alarm in Mrs Richards home - which for legal reasons can only be identified as "in the Watford area".

The alarm triggered audio recording devices, which caught the fatal attack on tape.

Richards had taken his anti-depression medication before setting out in a taxi from The Causeway unit to kill the woman he had married in 1992.

What had been a happy period came to an end in 1998. Richards suspected his wife of having an affair. She moved out, at one point staying in a woman's refuge to escape his attentions.

Richards, who had a history of being unable to deal with relationship breakdowns, had wanted to save the marriage. But, according to prosecution counsel, his feelings of rejection turned to rage and hatred.

On the day of the killing Richards had a drink at The Harvester, in Croxley Green, before going to what had been the family home at about 7pm. He smashed open the door and, knife in hand, grabbed the family dog.

When Mrs Richards came downstairs, he took hold of her by the hair and stabbed her four times in the chest and stomach.

She screamed for mercy and neighbours arrived at the scene in time to see the frenzied attack.

He was arrested in Gade Avenue, Watford the following day, after telephoning his uncle who called the police.

RIchards, 41, appeared at the Old Bailey on Friday, March 22, having pleaded guilty to manslaughter through diminished responsibility.

Judge Justice Hooper imposed a life sentence for the pre-meditated assault, saying there was a risk of the same thing happening again.

But Richards is likely to serve little more than three years in prison. The full sentence of eight years will only be imposed if he fails parole conditions.

The purpose of a life sentence was to allow the monitoring of Richards for the rest of his days, not to keep him locked up.

Family and friends in the public gallery, who had cheered the judge when gave his decision, reacted with disbelief and outrage when they realised the killer could be back on the streets in 2005.

March 25, 2002 17:00