A visibly drawn and tired-looking Peter Mills-Westley, a semi-retired heating engineer, spoke briefly to the Herald at his home just outside Gorey, Co Wexford.
He is the former husband of Jennifer Mills-Westley, the 60-year-old British grandmother beheaded by a crazed knife attacker in Tenerife's seaside resort of Los Cristianos on Friday.
Deyan Valentinov Deyanov, a homeless 28-year-old Bulgarian with a record of mental health problems and violence, is suspected of carrying out the grizzly killing and was remanded in custody early on Sunday morning by a Spanish judge.
Speaking at his countryside home in Tinnock, former husband Mr Mills-Westley told the Herald he has been unable to sleep since he heard the news of Jennifer's death.
"It's getting to the point now where I've had just two hours of sleep in three days," he said.
When asked how daughters Sarah and Samantha were coping with the ordeal, he replied: "Not good. We're all shocked.
"It goes without saying that we need to know why this man was out on the streets, and that needs to be looked into."
Granny-of-five Mrs Mills-Westley was knifed to death in a Chinese-owned tourist souvenir shop after she had complained of being followed by a man. She was stabbed 14 times by her assailant in a horrific and unprovoked attack. The attacker then cut off her head and left the shop with it.
Deyanov was arrested by police officers on a street nearby after he was tackled and held down by a security guard.
Shockingly, it has since emerged that an arrest warrant had been issued for the Bulgarian just three days before he allegedly stabbed and beheaded Mrs Mills-Westley.
Deyanov, who is now in custody with no possibility of bail, has come to the attention of police before and has been arrested on two occasions -- for criminal damage and causing bodily injury -- prior to Friday's shocking attack.
There are also reports that the accused has received psychiatric treatment before.
Reports have revealed that Deyanov entered a nearby shop on Friday and asked for a large knife.
When he was asked by the shopkeeper why he required it, he is alleged to have replied: "I'm going to kill someone."
He was thrown out of the shop but later stole a knife off a stall stand and attacked Mrs Mills-Westley.
Paying tribute to her murdered mother, daughter Sarah said she had been "full of life, generous of heart and would do anything for anyone".
"We now have to find a way of living without her love and light," she added.
Mrs Mills-Westley had retired some years ago and had an apartment on the north African island.