11/01/2012 03:40 GMT | Updated 11/01/2012 04:14 GMT

Heather Dyer: 'Noisy Neighbour' Stabbed To Death In St Helens By Paul Lyon Over Dispute

A young woman was stabbed to death by a neighbour who "snapped" during a dispute over her anti-social behaviour, a court has heard.

Heather Dyer, 22, was knifed three times by Paul Lyon, 45, just weeks before she was due to be evicted from their housing association flats in Chapel Street, St Helens, Merseyside, over parties and loud music.

Liverpool Crown Court was told that Lyon confronted Miss Dyer in the early hours of 23 July last year when she and seven friends were leaving her upstairs flat.

Lyon, who lived in the flat below the victim, "lost his temper" and stabbed her three times to the chest and stomach with a sharp fish filleting knife.

When her friends tried to intervene one of them, William Taylor, was also stabbed twice but survived the attack following a period in intensive care at hospital.

Lyon, who suffers severe epilepsy, denies the murder of Miss Dyer and the attempted murder of Mr Taylor, saying he acted in self defence after he had been attacked the group.

The jury of six men and six women will also consider a lesser, alternative charge of wounding with intent to cause grievous bodily harm to Mr Taylor.

Opening the case for the prosecution today, Andrew Menary, QC, said there had been "friction" between the neighbours for months leading up the incident.

He said: "She was in the habit of inviting people round and making considerable noise at all hours of the night.

"Mr Lyon made frequent complaints to the landlords but their efforts to prevent this anti-social behaviour did not succeed in resolving the situation.

"Accordingly, on 19 July, she was sent a notice to quit the flat by 25 September and Mr Lyon was told that this action had been taken.

"Sadly, the defendant did not wait for that date to arrive. Instead, he took matters into his own hands."

On the night before she was killed, Miss Dyer had spent the afternoon and evening drinking with friends at her home before they left to meet Mr Taylor and others at a pub to celebrate a 21st birthday.

At about 1.30am the group returned to Miss Dyer's flat and spent some time there before preparing to leave for Mr Taylor's home.

Lyon, Mr Menary said, had also been to the pub with friends and was returning home at about 2am when he became aware of music and noise from the flat above his own.

He remarked to a friend: "I'm f****** sick of this," and they resolved to call the police.

Mr Menary said the call was made at 1.54am but the police worker advised Lyon to contact his landlord or the local authority and officers did not attend.

The barrister told the jury they will hear from other residents of Chapel Street who described Lyon as "very agitated" at this stage.

One witness remembers him saying: "I'm going to f****** kill her if they don't stop playing the music - I can't get to sleep."

Another heard Lyon shout towards the upstairs flat: "You bloody slut."

At around 2.30am Miss Dyer's friends began to leave her flat to wait in the street for a taxi to Mr Taylor's. The victim herself was last to leave the premises.

As she left her home, wearing a nightgown and a leather jacket, witnesses noticed her arguing with Lyon on the doorstep.

Mr Menary said: "The order of what happened next is not altogether clear, but the defendant suddenly made a lunge at Heather and William Taylor tried to intervene.

"Both were stabbed by the defendant, who was by then armed with the knife.

"The other lads in Miss Dyer's group also then tried to intervene and the defendant was restrained."

Evidence from other neighbours described Lyon as "aggressive and angry", Mr Menary said.

He was shouting: "I can't stand the noise and this gang"; "You've no idea what you and your gang has done to me"; and "Come on, you think you're all big and hard 'cos you're in a gang - come on".

Various 999 calls were made and police arrived to a scene of "chaos", the court heard.

Mr Menary told the jury: "Mr Lyon may well have been justifiably mad at Heather Dyer and her constant and unreasonable anti-social behaviour.

"But nothing she had done in the past or on that night remotely justified him in launching an attack on her in temper, with a knife, taking this young woman's life and nearly taking the life of a young man."

Police found Lyon standing 6ft away from the body of Miss Dyer. He was covered in blood and had suffered a cut eye when he was restrained, the prosecutor added.

The defendant told police officers at the scene: "I stabbed her, I didn't mean to kill her. I stabbed them both, I'm sorry."

Paramedics found Miss Dyer unresponsive and after several attempts at resuscitation she was declared dead at Whiston Hospital a short time later.

The fatal wound was to the front of her chest which tore through the aorta and the left pulmonary artery. She also suffered two stab wounds to her stomach.

Mr Taylor was taken to hospital and treated for two stab wounds to his stomach, which caused damage to his liver and colon.

Following surgery and a period in intensive care, he made a "good" recovery, Mr Menary said.

Lyon told detectives Miss Dyer and her friends had abused him as they left her flat and he picked up the knife, which had been on a ledge by his front door, because he saw the gang approaching and blaming him for her forthcoming eviction.

During police interviews he said he was knocked to the ground and "swung" or "waved" the knife to "get people away".

Mr Menary said that account was "quite simply not true".

"Given the position of the injuries suffered by both Heather Dyer and William Taylor, the defendant cannot have been on the floor, thrashing about wildly and blindly with the blade when the stabbings occurred," he added.

The trial, which is due to last three weeks, was adjourned until 10.30am tomorrow.