Killer dentist Colin Howell has claimed he was trapped in a spider’s web woven by his former lover Hazel Stewart.

Taking to the witness stand to give evidence against his ex-mistress for a second day, Howell insisted that Stewart had seduced him from the start of their affair and that she was a willing participant in the murders of her husband Trevor Buchanan and his wife Lesley Howell.

“Flies go into spiders' webs because they think there is some food for them there and I willingly went after the bait and we got caught together in the trap,” said Howell.

During four hours of evidence he also told the court:

• If forensic tests had been carried out on the body of Mr Buchanan he may have been caught.
• He was the “mastermind” behind the murders but Stewart was happy to “join in the waltz”.
• Stewart entered into a “blood pact” with him when she had an abortion before the murders
• That everyone has the potential to kill

Stewart (47), from Ballystrone Road, Coleraine, denies murdering her husband and Howell’s wife in May 1991.

Their bodies were discovered in a fume-filled car in Castlerock in an apparent suicide bid.

Howell pleaded guilty to the murders last year and was sentenced to 21 years in prison.

Yesterday at Coleraine Crown Court Howell said he was the mastermind behind the murders.

“I knew I was the mastermind. I had the intelligence to put the plan together. I am the major person in this plan.

“If I had been able to take all the blame I would have, but in the last two years I thought Hazel is not my responsibility,” he said.

He insisted, however, that Stewart was a willing participant in the killings and that, just as he had facilitated her abortion during their affair in 1990, she facilitated the two murders.

“Hazel initiated the desire to have it (the abortion) and I was the one with the ability. It was a joint venture. Hazel wanted it and I facilitated it. With the murders, I wanted it and Hazel facilitated it.

“We were waltzing in time. This is the perfect illustration of the harmony we had together.”

“All the side-stepping was done together. I was not dragging her around the floor.

“I may have been the lead partner in that dance, but she was doing it in perfect harmony and willingly.”

Howell claimed that Stewart seduced him in 1990 and referred to their first sexual encounter when he said she invited him to her home to teach her the guitar.

“She was wearing a short denim mini skirt, a sleeveless low cut blouse and perfume and I knew I was not there for guitar lessons,” he said.

However, defence lawyer Paul Ramsey QC told him: “You are, and have been for most of your adult life, a sexual predator.”

Howell admitted that he was callous, merciless, devious and evil.

“Yes I was. I believe every human being has the potential to do what I did. But I did it and it sets me apart from humanity. All the adjectives put to me so far, I agree. That’s what I was, but I’m no longer that.

“What I did 20 years ago was the pinnacle of being callous and that has been hard to live with. My conscience became so crushed and all the things I had built around that, including my image, couldn't cope with that,” he told the court.

He said that he was now ashamed, remorseful and sorrowful for what he did and wanted to help the families of his victims to get closure.

“The events of 20 years ago, the impact of that is still alive and affecting people.

“I am here because of the victims. I have set myself up to be a punch bag.

“I am here today to give people a chance for their wounds to be closed. I would not dare to ask for forgiveness.

“If anyone chooses to forgive me that is a good thing. I believe someone doesn’t truly recover from an injury unless they forgive.”

When asked if he was a ladies’ man, Howell replied: “Only in part because beneath it all, even the most beautiful female or handsome man, there’s often insecurity.

“Because of my success and status and wealth, that made me attractive to some females and I got a positive response.”

He denied that he controlled Stewart, who he at times would drug before they had sex.

Mr Ramsey said that Howell had agreed during police interviews in 2009 that Stewart was frightened of him that she was “kind and innocent” and easily led.

Howell said, however, that he had been agreeing with everything police had said, treating officers like church elders.

He said that Stewart had deceived him and that she painted herself as a victim.

“It is the thing that draws you to her, she appears to be the victim. It is like an advert for an orphanage in India.

“You want to get your wallet out. But those adverts have businessmen behind them collecting money from people,” he said.

Howell said he was within hours of owning up to police in 1998 about the murders but that he underwent a “religious conviction” after meeting a girl at a Sunday night church service where he claimed she told him his sins had “been forgiven and forgotten by God”.

He eventually confessed to police in January 2009, saying that he was overwhelmed by guilt.