As he took the stand for a second day, Lillis, aged 52, maintained his poised, collected demeanour throughout the cross-examination by Mary Ellen Ring, BL for the prosecution.
During his 45-minute stay in the witness box, Lillis – dressed in a dark suit, white shirt and navy tie – admitted he had first posited the idea to his wife following their fight that they blame their respective injuries on a burglar.
He denied the accusation that he lied about the incident and concocted the burglar story because he killed his wife by hitting her three times on the head with a brick.
Ms Ring asked him whether he had still felt trapped even though by 11.30am on December 15, 2008, he knew his wife was dead. He said yes.
She then asked if he felt trapped on December 16, on December 20, on December 31. He replied that yes, he had, but denied that any notion of a continuing relationship with his mistress at the time, massage therapist Jean Treacy, had contributed to this feeling of being trapped.
“Were you feeling trapped on December 15 because of the lie you were telling, or was it something else,” Ms Ring asked.
“You were trapped because you had a new opportunity in life with Ms Treacy.”
He replied: “There was never any possibility of that.”
Ms Ring asked: “Are you sure about that?” He replied that he was.
Ms Ring then asked about the note found on Lillis’s desk, the note in which he wrote lines such as “She will never share your bed,” “She will marry Keith next June” and “You are running out of time!!!”.
Lillis said that this was for a script he was writing, prompted by a real-life incident years before when people passed a film crew working on an Irish Permanent advertisement linked to Crimeline, which in his idea could have provided cover for a robbery.
“The idea was sparked by the situation I was in,” he said, while denying that the note referred to his own life at the time.
“I had no reason to feel trapped,” he said.
Ms Ring said of the lacerations to Ms Cawley’s head: “The three head injuries were occasioned by the use of a brick used by you. You lied to the firemen, gardaí, your family, daughter and friends.
“You continued that lie because you had taken up the brick and hit her three times.”
She claimed he had continued to lie because these blows caused her death “and you were upstairs trying to cover up your actions”.
Lillis said firmly: “That is not true.”
Earlier, Ms Ring outlined the details of the injuries to Ms Cawley’s face, beginning with two marks around her upper lips and five on her lower lip. Lillis, she said, was able only to account for how four of these marks may have been made.
There were 11 other marks on Ms Cawley’s face, including a number of bruises around her eyes.
She pressed the point that in evidence heard earlier in the trial some of these marks could be consistent with Ms Cawley having had her face to the ground. Lillis maintained that she never had her face to the ground, and that during the course of the row with his wife and the accompanying physical altercation, her face was turned to the side, but never pressed to the ground.
Ms Ring also questioned him about his bloodied clothes, found upstairs in the family home the couple shared in Howth with their daughter. She queried why he had made “such a song and dance” about them when the clothing would actually have backed up his story about an attack by an intruder.
As for the “gaping lacerations” to the back of her head, Ms Ring mentioned in passing that Ms Cawley’s height was 5ft 10ins. Quick as a flash Lillis said: “She was 5ft 8.
“I was married to her and she was 5ft 8.”