A young Denbigh mother of two – bombarded with threatening messages from her former partner – went to her local police station to complain about him.

But she left before a formal statement of complaint was taken and a two days later he lay in wait for her as she returned home from a night out and murdered her, it was alleged in court on Monday.

Jason Liam Cooper – said to have brutally stabbed his former partner Laura Jayne Stuart, 33, with a kitchen knife he had taken to the scene – told in messages that he was planning to “erase her”, a murder trial jury was told.

Cooper, 28, also stabbed a man who went to her aid, Mold Crown Court was told.

Cooper of St Hilary's Terrace, denies the murder of Laura Jayne Stuart, 33, a mother of two, and wounding David Roberts with intent to cause him GBH, following an incident in Denbigh town centre in August of last year.

Prosecutor David Elias QC, opening the case to the jury on Monday afternoon, said that the defendant appeared calm and after the incident on August 12 sent a text message to a friend which read: "I have just murdered Laura".

Police officers arrived at the scene and he made a number of admissions to them, Mr Elias said.

They included: "It is not one of those psychopathic things where you go nuts for no reason.

"There is a reason for it. She thought she was going to live her life and leave me in the lurch and she would be as happy as Larry, f*** about and do as she likes. Not on my watch.”

In the lead-up to the killing, the prosecutor said that the defendant had sent a number of messages to Laura saying he was “angry, very angry” and said “did you honestly thing you would f*** me over walk away happy?”

Mr Elias said the police were called by both parties during the course of the relationship, but no formal complaint was ever made.

On August 9, just two days before she was fatally stabbed, Laura had gone to the police station to make a complaint about Cooper.

"Unfortunately, she left before a statement could be taken from her," he explained.

The prosecutor said on August 12, Cooper brutally attacked Laura in the street close to her home in the centre of Denbigh.

"He had taken a kitchen knife and was lying in wait for her as she made her way home from a night out.

"He ran towards her, stabbing her to the head, back and chest with the knife," he said.

David Roberts bravely stepped in to help as Cooper stabbed her repeatedly with the knife, said Mr Elias.

He grabbed Cooper by the shoulders and they grappled with each other but Cooper stabbed David Roberts to the shoulder, elbow and ear.

Mr Roberts fell to the floor and Cooper returned his attention to Laura Stuart, kicking her to the chest and the face as she lay bleeding on the floor, it was alleged.

Cooper remained at the scene for a few minutes, telling David Roberts’ father, Gareth: "I said I was going to do it and I did it".

The prosecutor said he appeared calm and assured to all those who arrived to assist.

He disposed of the knife and sent a text to a friend saying: "I just murdered Laura".

When police officers arrived, Cooper appeared "calm and in control".

Mr Elias said he made a number of admissions to the police in relation to the attack he had carried out only minutes before.

The injuries to David Roberts were treated successfully. Doctors did all they could to treat Laura Stuart’s injuries, but she died the following evening.

The couple had been in a two or three yea relationship and shared a rented property at St Hilary’s Terrace in Denbigh.

They argued regularly and Jason Cooper was occasionally violent towards Laura, it was alleged.

He did not like her going out or being in the company of other men. She moved out in early 2017 blaming Cooper’s controlling, possessive and jealous behaviour.

From time to time they attempted to resume their relationship, but arguments continued.

In the days leading up to the attack on Laura, Jason Cooper sent many messages to her via text and social media, the jury was told.

He was said to be more and more resentful and angry towards her.

The messages began with “horrible insults” and ended with direct threats to her life, said Mr Elias.

Police recovered from his phone a message "With me now Laura I’m not upset over u anymore I’m not heartbroken anymore I’m angry very angry. And I intend in focusing my anger on you lying b*******”.

Another read: "Did u honestly think u could f*** me over six weeks ago and walk away happy”.

The prosecutor said another message read: "Understand this loud and clear I know what you done and I know what u doing? And I will not be holding back.”

On August 6 he went two messages to Laura demonstrating extreme jealousy, the prosecutor said He messaged a man, accused him of seeing Laura behind his back and added “I’m ready to kill mate that’s how I feel. I invested three years plus of my life into her and she f***** me over”.

The same day he sent "insulting and threatening messages" to Laura, including: “Im gomma ruin u Laura” and “Ruin u get out of Denbigh”.

On the evening of August 9 he was said to have been abusive towards her at the Golden Lion, threw a handful of coins on the floor next to her and she was visibly upset.

He later messaged her “The amount of s**** u causing Laura Im putting end to it I want u out this town”.

Another read : “U have pushed me as far as I will go now. My advice to u Laura is run”.

The defendant had also sent David Roberts a Facebook message saying “I can’t tell u over msg wat I will do” and “I told Jamie she is a cancer and I will erase her”.

He also sent a message to another man saying l: “I will erase her as a cancer she is” and “I will put end to her s*** and it’s so easy for me and it will happen”.

On the evening of the August 10 he sent another man: “I have had thoughts of murder and suicide all in 1 lately” and “I don’t want her mate I would kill her right now if I seen her”.

The jury has been shown CCTV at Denbigh and also body worn camera footage from police officers who attended the scene.

The footage shows Laura falling down onto the ground near to the Halifax Bank close to the Love Lane junction.

Laura could be heard in conversation with a police officer about who had attacked her.

She said that she was standing there and “he came running at me and put something in my back.”

Laura said that it was “really painful”.

The trial before Mr Justice Simon Picken is proceeding.