Two former lovers have gone on trial accused of murdering Hartlepool mother-of-three Kelly Franklin.
Kelly was stabbed more than 30 times by her ex-partner Torbjorn Kettlewell as she saw a friend onto a bus in Oxford Road, Hartlepool.
Kettlewell is alleged to have been driven to and from the murder scene by his co-accused, Julie Wass.
A jury at Teesside Crown Court heard Kettlewell and Ms Franklin had been in a relationship for 12 years which had gone sour.
Kettlewell, who changed his name from Ian because he was fascinated with a video game character called Torbjorn, lost custody of their children after he accidentally shot one of them in the face with a high-powered air rifle.
At around 9pm on August 3, he searched for her and "brutally" attacked her in Oxford Road with a kitchen knife he took from his flat.
"Kettlewell was a coercive, controlling, and abusive man," said Jamie Hill QC, prosecuting.
"He spent his life drinking, surrounded by computer games, and perhaps of more concern, trying to draw Kelly into his sexual fantasies involving other women.
"He was obsessed with weapons and the Army, and shot one of the children in the face with an air weapon while cleaning it.
"That led to the couple losing the children.
"He blamed Ms Franklin, and a social worker, for the loss of his children - it could never be his fault.
"By the time of the killing last August he had split from Ms Franklin, 29, and was living in a flat a couple of miles away across Hartlepool.
"He was trying to get back with Ms Franklin, she was not interested, and was moving on with her life.
"We say Kettlewell decided that if he couldn't have her, no one else could."
Mr Hill said the fact Kettlewell had killed Ms Franklin was 'not in dispute', but he denies murdering her.
"He told police he went to confront her," added Mr Hill. "He said he couldn't remember fully what happened."
The jury heard Julie Wass spent most of the day of the killing with Kettlewell at his flat.
The pair were tracked going in her car to woodland at Trimdon, which prosecutors say was to research a hiding place for later.
Prosecutors say Wass drove Kettlewell to Ms Franklin's home in Kipling Road shortly before the killing.
After the killing, Wass drove Kettlewell to the same wooded area in Trimdon, before she returned to the scene with her brother.
She gave police differing accounts of her movements that night, claiming the first time she had seen Kettlewell was when he got into her car after the killing, and ordered her to drive him away.
Mr Hill said Wass had driven Kettlewell to the murder scene, he had knocked on her door, while she had driven around locally looking for Ms Franklin.
Wass is alleged to have spotted Ms Franklin at the bus stop in Oxford Road, then she is alleged to have rang Kettlewell to tell him where Ms Franklin was, knowing he intended to harm her.
Mr Hill told the court that he went straight there and confronted Ms Franklin, pulling her along the street before getting out a kitchen knife.
"It was broad daylight, and several people saw what happened but those witnesses were too shocked to intervene," said Mr Hill.
"Kelly suffered over 30 stab wounds, many to her neck and body, some wounds pierced her heart and lungs, the power of the blows broke several ribs and major arteries were severed.
"It was impossible for anyone to save her from that attack and anyone watching it could have been in no doubt that Kettlewell was intent on killing her."
The jury was told Wass went back to the murder scene, which by then had been cordoned off and spoke to police, tearfully telling an officer she had witnessed the murder.
She identified herself as the victim's neighbour and said she had known them both for years.
She also warned police Kettlewell could be going to harm a social worker involved in the custody case.
Wass was captured on the officer's body-worn camera saying: "He has always sworn down if he ever killed Kelly he would go for the social worker."
Kettlewell and Ms Franklin had dated since they were teenagers and their families became concerned about his behaviour towards his partner and their three children, the court heard.
Social services got involved, Mr Hill said, and there were "particular concerns about Mr Kettlewell's coercive and psychologically abusive behaviour towards Kelly".
He would try to blame everyone but himself, Mr Hill said.
"The whole picture is of someone who is utterly self-centred and indeed narcissistic," he said.
Ms Franklin "waited on him hand and foot" and although she loved her children, at times she was so busy doing his bidding she could not care for them properly, the court heard.
They were taken into care when he accidentally shot one of them and Ms Franklin tried to cover for him, Mr Hill said.
The couple split in 2017 and she was helped by a domestic abuse charity and took parenting classes to win them back.
It was then that Kettlewell bombarded her with Facebook messages, Mr Hill said, threatening her and obsessing that she had a new partner.
Mr Hill said: "This obviously did not prevent him from having other relationships himself, including one with his co-accused Julie Wass."
He said Kettlewell was obsessed with sex and was determined to get Mrs Wass, who has four daughters, and his ex-partner together.
Mr Hill said: "He was hoping to draw her into his sexual fantasies and involve her with Kelly as well."
He said Wass would spend a long periods at his flat, would drive him around, go shopping for him and was "generally available at his beck and call".
He added: "It is also apparent that Julie Wass immersed herself in the relationship with Mr Kettlewell and Kelly Franklin, not just by sleeping with him, she seems to have been completely in his thrall."
Kettlewell was arrested the following day after he was found in the home of another woman.
The court heard no murder weapon was ever found, but there was a knife missing from a block in Kettlewell's kitchen which a forensic scientist said matched the size and type used to inflict the fatal injuries.
Kettlewell, 30, of Oval Grange, Hartlepool, denies murder on August 3.
Wass, 48, of Kipling Road, Hartlepool, denies murder.
She admits assisting an offender.
Mr Hill told the jury: "A defendant has only to intend serious harm to be guilty of murder, although we say Mr Kettlewell intended to kill Ms Franklin.
"It may be in due course he will say he is guilty to manslaughter on the grounds of diminished responsibility, which is a partial defence.
"It is open to any defendant to call medical evidence to say he has an abnormality of mind.
"It is true Kettlewell has been in contact with mental health services over the years.
"Whatever disorder he may have, we say he is an intelligent man who knew what he was doing.
"His mental disorder is not at such a level as he can hide behind it as a defence to murder."
Mr Hill said Wass was guilty of murder as a 'secondary party' by deliberately assisting Kettlewell knowing what he planned to do.
The trial is proceeding and is expected to last two weeks.