Drug mule Michaella McCollum lied about sectarian threats that she claims forced her to flee Ireland overnight for Ibiza.
McCollum (23) claimed in her much-criticised RTE interview that she left her home in the North for "sectarian" reasons and said she was told to leave the area under threat.
However, her mother previously told the same documentary makers that her daughter planned her trip to Ibiza months before travelling in 2013.
Two local politicians also cast doubt on Michaella's claims of sectarian threats.
McCollum, interviewed after her release from a Peruvian prison, suggested that following the threats, she decided to leave for the party island "overnight".
But the Herald can reveal this account is directly contradicted in an interview given by her mother Norah McCollum in 2014, for a documentary called Michaella, Peru and the Drugs Run.
Her mother said her daughter had been planning to go to Ibiza since the beginning of 2013, despite protests from the family. She travelled there in June 2013.
Both the 2014 documentary and Sunday's interview were broadcast by RTE and created by Below the Radar, the same production company that has been given access to McCollum's family.
"Sometimes when I was faced with problems. I'd run away from my problems instead of actually facing them," McCollum said at the weekend.
"I was living in an area that caused me a little bit of problems. I was told to leave the area as soon as possible or something would happen.
"I didn't have the money to pay a deposit for a new house ... to rent a new house. I was a little bit too proud to go back to my family's home. I literally had that moment that I would go to Ibiza.
"I'd go on vacation and leave my problems here ... it was an overnight decision. My family were highly against it," she added.
But there was no discussion of sectarianism, threats or overnight decisions when her mother was interviewed in 2014 about the Ibiza trip.
She was joined by a camera crew for a visit to Peru to see her daughter in prison.
"It was probably early last year (2013) she talked about going to Ibiza, to work during the holidays," Ms McCollum said in the documentary, which was broadcast by RTE in July, 2014.
"But I wasn't really happy about it so I was hoping that she wouldn't, that it never came to that.
"So then she did decide to go, I wasn't happy with her going either. None of us wanted her to go," Ms McCollum said.
Trevor Birney - whose line of inquiry included questions about McCollum's bun hairstyle - failed to address the inconsistency in the interview broadcast by RTE last Sunday.
Mr Birney is the CEO of the production company and was listed as the director of the 2014 documentary.
Questions to the filmmaker's company about why the inconsistent story went unchallenged, were unanswered yesterday. A spokesperson said that Mr Birney was in Cuba.
The interview has been criticised as a PR exercise designed to make McCollum look like a victim.
It is not the first time that McCollum has lied. After being arrested at Lima Airport in 2013 with €2m of cocaine, she falsely claimed that she had been threatened by drug lords. She later admitted this was untrue.
The question of sectarian threats against McCollum was also rubbished by politicians in her home of Dungannon, Co Tyrone.
They said they were frustrated and annoyed that the criminal has used the excuse of sectarianism as the reason for leaving - adding that she was never involved in violence.
Representatives said that McCollum had friends from both the republican and unionist communities.
Dungannon councillor Walter Cuddy, who runs newsagents in the town, told the Herald he knows the McCollum family and was "surprised" at the sectarian explanation.
Mr Cuddy said that McCollum had also lived in Belfast - where she studied photography and worked as a model - with flatmates from unionist and republican background
"The family have never been involved in any violence in Dungannon. To my knowledge she was not the type of person to be involved, unless something brewed-up," he said.
Councillor Wilbert Buchanan said sectarianism was not an issue at the time McCollum decided to leave.
"She's only a young girl. The Troubles were a long time ago. Things have well settled down. I wouldn't be aware of any sectarianism in recent years. It's a great place to live," he said.
Denise Mullen, another local councillor in the area, said she knows what real sectarian issues are.
"I witnessed my father being shot dead and also my mother being shot at just four years old. I had no notion of moving away," she said.
Production company Below the Radar has made eight RTE-commissioned documentaries since 2009.
The 2014 documentary about McCollum followed her mother and her sister Samantha McCollum as they visited her in jail in Peru.