A sex therapist's husband has been convicted after blackmailing a technology firm chief executive and stalking his Chanel model daughter.
Darren Cooper, 54, made false abuse allegations against New Zealand born businessman Peter Gillingwater after a High Court battle over a £1.2million home.
That property was co-owned by Cooper's sex therapist husband Thain Kleinhentz and Mr Kleinhentz's ex Mark Harrison, which became subject to a legal fight in 2020.
Cooper has now been found guilty of attempting blackmail in a bid to claim money for Mr Kleinhentz and of stalking Peter and Aimee Gillingwater.
He also made allegations against Aimee, a model and skater, causing her to lose work with Chanel, it was said.
Cooper was due to be sentenced at Inner London Crown Court on Monday but Colin Whitshaw, defending Cooper, asked for an adjournment for reports to be prepared.
The defendant appeared in court wearing a blue suit and was granted bail ahead of sentencing on December 4.
Cooper has been issued with a restraining order banning him from making contact with Peter, Aimee and Carol Gillingwater, along with Mark Harrison.
Aimee Gillingwater is pictured at a fundraiser for Young Lives vs Cancer hosted by Tara DuRoss at St Pancras Renaissance Hotel in London on November 22, 2023
Darren Cooper (pictured), 54, made false abuse allegations against New-Zealand born businessman Peter Gillingwater after a High Court battle over a £1.2million home
Aimee Gillingwater and her father Peter Gillingwater are pictured outside Inner London Crown Court where they were attending Monday's hearing
The order prohibits Cooper from posting anything about them online.
Mr Gillingwater and his daughter Aimee attended the hearing on Monday.
Cooper created a newspaper-style blog that falsely accused Peter Gillingwater, 52, of drug dealing and sexual abuse.
He included the businessman's model and singer daughter Aimee, 28, in his 'abusive and derogatory' online campaign and threatened to destroy her career, it was heard.
Inner London Crown Court was told he eventually demanded sums of £250,000, £100,000 and £80,000 to close down the blog and delete abusive posts on X and LinkedIn.
Cooper, from Clapham in south London, denied the charges but was convicted of blackmailing Mr Gillingwater between January 14 and July 19, 2023.
He was also found guilty by the jury of stalking the father and daughter between January 1, 2021 and July 19, 2023.
Cooper's husband, South Africa-born Mr Kleinhentz – an NHS health adviser – lost a High Court claim for a share of his previous partner's house in Barons Court, west London, which sold for £1.2million in 2015.
Counsellor and sexual health adviser Thain Kleinhentz (left) said he and Mark Harrison (right) had a 'loving relationship' during which they lived together in a £1.2million house in London
The home in Fulham owned by Mark Harrison sold for £1,212,500 in May 2015
He said he was owed £250,000 after sharing the property for many years as the partner of the property's owner Mark Harrison but lost after a two-day trial.
Mr Gillingwater gave evidence on behalf of Mr Harrison, resulting in Cooper creating a blog condemning his character and behaviour in the witness box.
Jonathan Whitley, prosecutor in the case against Cooper, said: 'He repeatedly posted abusive and derogatory material online about them and demanded £80,000 and then larger sums of £100,000 and £250,000 to remove the material.
'This is vengeful behaviour that arises from a civil court case in 2020 when Mr Kleinhentz said he was entitled to a share of the property owned by Mr Harrison.
'Mr Kleinhentz lost with an order for costs against him and he declared bankruptcy.
'This defendant is his husband and believes he should have won the case and blames the complainant for losing.
'Cooper admits posting the material and sending emails to the family and company board members and says he was justified in doing that.'
Mr Gillingwater told jurors his family took the decision to go to authorities after receiving an email that referred to the 'gang bang' of his daughter.
The businessman said: 'She was a significant target. The language and implication was unacceptable and we decided it was time to take action about these hundreds of emails and documents and approach the police.'
He also received a phone call, targeting his daughter's upcoming show.
He said: 'I recognised it as Darren. He said he was going to destroy her again and this was a threat to her and her gig.'
Mr Gillingwater had already received a demand for £100,000 for the blog's removal from Cooper, one of three separate payment demands for different amounts.
He said: 'It was another attempt to solicit payment to see if we were prepared to pay for the content to disappear. We did not respond as we thought he was getting desperate.'
Another email from Cooper threatened to go to the national press with his allegations.
The campaign did result in the CEO leaving a board associated with one large blue chip company and distancing himself from a charity, where he was a mentor.
Mr Gillingwater told the trial: 'It worried me that my reputation would be ruined by these allegations.'
Cooper had created a blog that described Mr Gillingwater in the headline as a 'Paedo', adding that he 'lies in court about previous sexual abuse allegations'.
Cooper also wrote about 'lies exposed' regarding the tech boss, accusing him of drug dealing and addiction, child pornography, cocaine supply and making false accusations.
Prosecutor Mr Whitley said: 'The blog posts were sent to the family and others, including board members of the man's company to denigrate his reputation and the rest of his family.'
Cooper also sent messages to the business leader's model daughter, including saying: 'OMG. I saw on twitter your dad raped you, b******.'
He also threatened to damage her career by writing she was involved in child pornography available on the dark web.
Mr Whitley said: 'This campaign has caused serious distress to the family and the daughter says she has lost modelling work and has been unable to post on social media.'
Cooper and Mr Kleinhentz were both arrested, but police charged only the defendant, who admitted in a statement creating the blogs and emailing the family.
Cooper told officers both he and his husband were the victims of 'slurs' and he was simply 'trying to shine a light on abuse', complaining his husband did not receive justice at the High Court.
The couple are believed to no longer be together.
Cooper has been bailed until November 27.