Double killer Colin Howell told police he injected his former lover Hazel Stewart with a drug used to sedate intensive care patients to remove “the guilt” of having sex with the man who she had helped murder her husband.
he details are contained in a Public Prosecution Service decision not to charge the Coleraine dentist for the rape and sexual assault of the former Sunday School teacher.
Stewart waived her right to anonymity last year to allow the fresh allegations against Howell to be reported.
Despite an appeal by her solicitor Kevin Winters of KRW Law, the PPS have once again said Howell will not face a further trial for raping his former partner.
The detailed PPS decision gives an insight into the bizarre and controlling relationship between the mother of two and the Coleraine dentist that has never been made public before.
Hazel Stewart made two new allegations against Howell in 2017.
The first was that in and around 1991 to 1993, the killer dentist raped her in her family home at Charnwood Park in Coleraine after injecting her with a powerful drug, more commonly used to sedate intensive care patients.
During an interview with police, Stewart said she had been injected with the sedative rendering her unconscious.
She told specialist officers that while she did not recall sexual activity on that occasion, she felt afterwards he had sex with her because of how her pyjamas bottoms were when she woke up the next morning.
Howell was taken from Maghaberry where he is currently serving a life sentence and questioned about the fresh allegations.
While he admitted drugging and having sex he claimed it was consensual.
A written PPS decision, sent to the mother of two’s legal team, states: “It is clear there was sexual intercourse because Mr Howell confirmed with police that he had sex with you on that occasion after he injected you with midazolam (Hypnovel). You both say it happened in your bedroom”.
In a statement to specialist public protection unit officers in 2017, Stewart said Howell told her the drug would relax her because she was “stressed and emotional at the time” but said she did not know it was so that he could have sex with her.
The former Sunday school teacher told police: “I had no control over anything and just let it happen.”
When questioned in 2018 about the allegations, Howell denied she was unconscious during the sex and said she communicated with him “by mumbling”.
He claimed she consented to the injection and the sex. During the interview he said that around that time it was not “unusual” for him to give her a sedative drug prior to consensual sexual activity claiming the purpose of the sedative was to “relax” her and for her “arousal”.
The second allegation centres around sexual assaults in Howell’s dental surgery in Ballymoney. The assaults were alleged to have taken place both in the upstairs and downstairs surgery.
The PPS noted: “You (Stewart) said he gave you laughing gas which made you feel as if you were drugged or drunk, but you were never given so much as to render you unconscious.
“In your 2017 statement you said that he increased the amount of gas he gave you each time.
“In that statement you said he ‘might have touched my breast and leg or had me touch him, I didn’t like it ... I can’t really remember, it just got out of control, I was extremely angry and frustrated’.
She told police that Howell was “experimenting” with her and she felt he wanted to see what she would remember.
“I let him do this but at the same time I felt I had no control … I was scared of what he might do if I didn’t go along with what he wanted,” she told police.
Howell once again admitted to drugging his former partner but said it was with her consent.
He claimed because of her Christian beliefs and the “guilt of engaging in sexual activity”, the sedatives helped her relax and cope with the guilt so that she “could enjoy the sexual activity”.
The alleged sexual assaults were said to have occurred after the murders of their spouses, Trevor Buchanan (32) and Leslie Howell (31).
The deaths, that were originally treated as a suicide pact, only came to light in 2009, when Howell's then wife Kyle forced him to confess to police.
Howell told police he had killed Trevor and Lesley at their respective Co Londonderry homes in May 1991, attaching part of a baby's feeding bottle to a garden hose, gassing them with carbon monoxide as they slept.
Howell then drove them to a row of houses at Cliff Terrace, Castlerock, known as the Twelve Apostles. One had been owned by Lesley's father, Harry Clarke, who had collapsed and died at his daughter's home 12 days earlier.
In its garage, he placed Mr Buchanan in the driver's seat and Mrs Howell in the boot with family photographs beside her and her personal stereo playing.
Howell connected a length of vacuum hose to the exhaust, with the other end in the boot, switching on the ignition before cycling home.
Kyle, who returned to her native America after her husband's confession, had known for a decade that the man she was married to had killed Mrs Stewart's then husband and his first wife.
She later told a tabloid newspaper that he blackmailed and coerced her into keeping his secret.
"Everyone thought he was this great Christian guy but they were so wrong. He was a monster,” she said.
Howell pleaded guilty in 2010, implicating Stewart in the plot and later gave evidence against her at her trial.
He must serve at least 21 years for the double murder. Ms Stewart was sentenced to a minimum of 18 years.
She is serving her jail term in Hydebank Wood, where she is described as a ‘model prisoner’ who spent lockdown baking in the prison’s kitchen for NHS workers.
Howell is also serving a separate sentence for sexually assaulting five female patients while they were under sedation at his dental surgery in Ballymoney.
While the allegation of a sexual assault on Stewart was known at the time and featured in The Secret, journalist Deric Henderson's book - later adapted into a TV series about the double murder - it was never raised in her defence.
ITV have agreed not to re-run the series, starring actor James Nesbitt, until any legal process linked to the new allegations are concluded.
Howell, now aged 62, was taken from Maghaberry Prison in 2018 and questioned by detectives from the PSNI public protection unit.
A leading member of the evangelical church, Howell was addicted to online pornography, a serial adulterer and admitted abusing female patients under heavy sedation at his Ballymoney clinic.
Stewart claims she was in a coercively abusive relationship with the dentist who manipulated and sexually abused her during their time together.
This was not raised at her original trial but was at her appeal, which was rejected in 2012.
However, her legal team argue that not enough was known about coercion at the time and since then the law has come to recognise the role this has on victims of abusive relationships.
Coercive control is still not law in Northern Ireland but Justice Minister Naomi Long is currently progressing the Domestic Abuse and Family Proceedings Bill through the Assembly. The legislation is in the final stages and will make emotional, coercive or controlling, and economic abuse a crime.
In a detailed written PPS judgment on the case, a senior prosecutor told Stewart’s legal team: “Having carefully considered this case, I have decided not to prosecute Mr Howell for any further criminal offence”, adding that the test for prosecution was not met.
“I concluded there was not a reasonable prospect of securing a conviction against Mr Howell for committing any sexual offence against you”, the PPS added.
Kevin Winters of KRW Law said he was disappointed at the decision, saying his client “rejects absolutely the suggestion made by Howell that she consented to sedation for the purposes of sexual activity.
"Secondly, she asserts that at all times she has been consistent in her allegations made to police”.
