A 21-year-old American woman jailed almost three years ago for murdering her mother in a Bali hotel room and stuffing the body into a suitcase has made an extraordinary confession on YouTube about the killing.

Heather Mack's three-part YouTube statement seems to be designed to absolve her boyfriend, Tommy Schaefer, of his role in the slaying, for which he is serving 18 years in prison, and to clear her own conscience.

"Since I've been a kid I've heard 'the truth sets you free, the truth sets you free'. And I never understood. But I'm Heather Mack, and I wanna be set free," the Chicago native says in the video .

"I don't want to live in a lie anymore. When I was 10, my mother killed my father in a hotel in Athens, Greece.

"Two weeks before I came to Bali, I found out that she killed my father, and I made it up in my heart, in my mind, in my soul, in my blood, in the oxygen running through my body, that I wanted to kill my mother," she said.

Sheila von Wiese-Mack told her friends that her daughter Heather was a difficult teen who she couldn't control. (The Caxton Club)

Mack and her mother, Sheila von Wiese-Mack, went on holiday to Bali in 2014 in what was meant to be a "new beginning" for their strained relationship, according to the Chicago Tribune .

But Mack says she started to plot a symmetrical end for her mother to demise under what she says are similar circumstances to that of her father Jim, who officially died of a pulmonary embolism in 2006.

Schaefer, whose baby Mack is being raised in a plush prison that allows her access to the internet as well as a host of other privileges, confessed to hitting von Wiese-Mack with a heavy fruit bowl before cleaning up the hotel room and trying to dispose of the body.

Heather Mack said it was her who sent incriminating messages from Tommy Schaefer's phone, because she didn't want to get arrested alone in a foreign country. Schaefer admitted in court to bludgeoning von Wiese-Mack during an argument over Heather's pregnancy, but it's thought that von Wiese-Mack already knew she had a granddaughter on the way. (Getty)

But in her video "confession" Mack says she "trapped" her "innocent" beau in Bali and forced him to help her try and get rid of her mum's remains.

"I killed her myself," she said.

"I don't regret killing my mother, and as evil as that may sound, that's my reality...But I regret bringing Tommy into it."

But von Wiese-Mack's sister told the Tribune her niece cannot be trusted to tell the truth.

The suitcase the pair stuffed von Wiese-Mack's body into. (AFP)

"Heather Mack's stories about her relationship with her mother and the events in Bali have changed so many times it is impossible to discern truth from deception," Debbi Curran said.

"However, her accusation about Sheila killing Jim is completely false. Sheila loved Jim very deeply and was devastated by his death."

Further complicating matters, along with Schaefer's courtroom confession that he killed von Wiese-Mack after an argument over Mack's pregnancy, is the conviction of Schaefer's cousin, Ryan Bibbs.