Prime Time tonight revealed that Creaven made multiple online approaches to around 100 children.
Ms Piggot told the programme it was hard to reconcile the professional sports producer whom she worked alongside for 15 years at RTÉ with the man who was videotaped by the Leeds-based vigilante group Predator Exposure which confronted Creaven when he travelled there in 2017 to meet whom he thought was a 13-year-old girl.
"It was like watching a film. I found it really hard to believe that that was the same person.
"I found myself looking really closely and thinking, are you sure they've got the right guy? Because it was just so alien to put these two people together. It just didn't make sense,” she said.
The group’s exposure of Creaven led to his arrest by Leeds police and a subsequent jail sentence for sexually grooming a child. He served 10 months of an 18-month sentence in the UK for the crime.
A subsequent investigation by gardai into Creaven’s online activity and trips abroad led to him pleading guilty to 10 charges including sexually assaulting children, child exploitation and possession of child pornography.
It also emerged following his sentencing hearing last Friday that Creaven had travelled to a number of locations in south-east Asia, including the Philippines where he was convicted of abusing children.
Ms Piggot said she now finds it strange that he didn’t keep these trips quiet.
"I remember from way back he was always going to unusual places, I suppose, for holidays, Vietnam, Cambodia, jump out and the Philippines as well. And I'm sure there were other places.
"They were definitely his own personal holidays. And no, he never hid it, which is even —so bizarre."
She said that despite initially feeling sorry for Creaven as a colleague, she has since realised that she never really knew him.
"I was feeling a sense of pity towards the Kieran I knew and I had to say to myself, but, no, this is the same person. So that was really hard, really hard, because he just never came across like that. And that's the really scary, scary part. We trusted him.
"That clearly sets you back a bit when you realise what people are capable of. And I think that's the most frightening thing, that someone can present themselves in a way, and how they can be this completely different person, and everyone will be so unaware of. I mean, that's really, really frightening."
Meanwhile, Prime Time revealed that six of the 100 children Creaven contacted online had significant contact with him, including two who have yet to be identified.
Irish priest Fr Shay Cullen, a Columban missionary priest who founded The Preda Foundation in the Philippines to rescue children there from sexual abuse and exploitation, described the sordid world of sex tourism there.
"They have the children in a room, in a bedroom, and they connect up and that's it. They video the child on the cell phone and it's broadcast live,” he told
"The customer in Ireland will send his instructions and say, ‘Let the children do like this or let the children undress’, and then, ‘Don't you have someone to do some sexual act there on the child?’ So that's how it goes on. And they have a friend down in the Western Union office and at the same time, live, they collect the money. And then he orders another show. They call it a show."
He described the country as the “epicentre” of sex tourism and abuse of children and he has been working since 2017 to bring about a change in the law in Ireland that would restrict convicted paedophiles from travelling to destinations that are known for sexual abuse and exploitation of children.
"All they have to do is pass this law and put a stamp in their passport to say they're convicted paedophiles. I see in Ireland that they were able to implement imposed travel restrictions overnight because of the Covid. But the paedophiles going abroad to the Philippines like this Creaven to abuse children?" he said.
"I see Ireland is opening an embassy in Manila. We’d highly recommend they send out a federal police officer to help us track down the Irish paedophiles. And if they'll work with us in finding a victim, we will get a conviction,” he said.
Meanwhile, Detective Chief Superintendent Colm Noonan of the Garda National Protective Services Bureau revealed the unit is currently investigating almost 1,000 “actionable referrals” concerning unlawful images of children in Ireland.
"We are working every day to try and identify the victims and the offenders in those cases, and that's the appeal, because somewhere there is somebody who is a victim of these crimes."
In a statement issued tonight, RTÉ said: "Kieran Creaven successfully concealed his abhorrent and criminal behaviour from those closest to him, those that worked with him and the authorities in a number of jurisdictions until his arrest in November 2017.
"RTÉ was appalled to learn the details of the crimes he committed for which he was sentenced last Friday.
"Since his arrest, RTÉ has provided every assistance requested by An Garda Síochána to carry out its criminal investigation, including making available Kieran Creaven's workplace equipment and personal belongings in RTÉ.
"For RTÉ to have conducted any separate investigation while this extensive and forensic criminal investigation, and process, were ongoing risked jeopardising the recent conviction of Kieran Creaven.
"We have asked the gardaí if there is anything further RTÉ can do to assist in their investigations, and we are also seeking clarification from them regarding the investigation.
"RTÉ continually reviews its policies and procedures, including RTÉ's Technology Usage Policy, and we are satisfied that we have robust policies in place. However, in light of these events and given the criminal investigation has now concluded, RTÉ will seek independent specialist advice to evaluate our policies and procedures in this area.