An identical twin had a “premonition” she was going to be attacked in the weeks before she was stabbed to death by a stranger in daylight.

Ann Cook had been walking her little dog through Munden Park, near the A41 in Watford, in 2000 when she was brutally killed.

Her harrowing story – and the tale of how her killer was eventually caught – was aired on Sky channel Crime + Investigation at 9pm last night (Monday.)

What makes the case all the more devastating is that her parents, Peter and Margaret, who were on holiday at the time, initially had no idea which of their daughters was dead.

The day she was killed, Police Inspector Anthony Munday, 65, was nearby investigating the case of an armed man who had a vendetta against his ex and her new boyfriend.

 

Suddenly, a dog walker came rushing up to him in a panic and told him he had just found a dead body in the nearby field.

Speaking to the Watford Observer ahead of the show, he said: “I asked him to repeat it again, almost to give myself a second to think.

“But his body language, his tone of voice, told me he wasn’t mucking around.

“Less than ten minutes later I was in a parkland I didn’t even know existed and I sadly saw the body of a young girl. She looked really young and had her dog next to her.

“A police officer checked the side of her neck to confirm she had died.”

The next few hours were crucial: her dog was taken to a vet with forensic officers to try and preserve evidence and a cordon was put in place.

“It was really awful,” he added. “The incident in itself was outrageously horrible, but any dead body in the job is a tragedy.”

Anne lived with her mother and father in the nearby Meriden Estate and her twin sister Susan had recently moved out to live with her husband.

The area she was killed is usually a safe, quiet park – but Anne became unusually afraid that something bad was going to happen to her.

Senior investigating officer Les Bolland told the documentary: “A relative heard her concerns and gave her a pocket knife to carry around with her.

“Living in a place like Watford, this was a heightened level of paranoia, but the tragic thing is that her fears came to pass.”

A manhunt ensued and her heartbroken twin sister, Susan, made an emotional appeal on television – but the police trail went cold.

Then, a breakthrough happened. People on the estate reported having seen a man wearing a bloody vest walking through the pathway near their back gardens on the day she was killed. Only people with local knowledge would know it was there.

Others said they had seen a man fitting the same description running across the M1, round the back of the estate.

Police looked into people who live on the estate and have prior convictions and narrowed their search down to one man: Leon Amos.

Amos had a previous conviction for rape in 1985 and the attempted rape of another girl after spending eight years in jail.

The only problem was that Amos had disappeared. When his parents, who lived on the estate, were questioned, his father Peter denied having a son called Leon.

The murder weapon, a kitchen knife taken from the home of Amos's girlfriend, was later found along with traces of blood.

Police also found Miss Cook's mobile phone, stained with her blood, in a tin box in the flat of Amos's brother Jerry, 39.

He was arrested nine days later and put on trial, where the judge said he had set out with murder or rape in mind.

Amos, 36 at the time, was found guilty at Reading Crown Court in February 2001 and jailed for life.