Recalling that time, Ms Karnstein said: 'Mum was too deeply in love by then and believed she was safe because he underplayed his convictions.
'When she sent me the links to his conviction I went hysterical and called her and said "Mum you can't do this, he's going to kill you too!" - and that's what happened.'
After being charged with Janet's murder, Mellors was found dead while in custody at HMP Manchester on February 25 while awaiting trial.
Ms Karnstein's family are now searching for answers from the Ministry of Justice after claiming her mother reported Mellors' behaviour to his probation officer multiple times.
She said: 'Wanting to give him the benefit of the doubt, mum stayed with him until New Year, because she wanted him to be able to celebrate his first one out of prison - but she didn't know that'd be her last.
'She even offered for the two of them to be friends, but then he started following her on her way to work.
'She used to call me worried about what would've happened if she didn't turn around and see him.'
Ms Karnstein, 20, spent ten months sat across the dinner table from her mother and her convict boyfriend.
On January 29 last year, after an altercation at her house, Mrs Scott was stabbed by Mellors before he ran her over.
Ms Karnstein said: 'I was at university when it happened, and as soon as the police turned up at my door I knew he'd done something to her.
'They told me that it started at the house, where he stabbed her, but she was still alive until he'd driven a car into her near his home.
'When they told me what happened my world came crashing down, as much as I wasn't surprised by what he'd done, I never thought I'd lose my mum.
'He manipulated everyone he met but especially my mum and he completely wore her down.
'My mum was the kindest, most loving and forgiving person there was and I still can't believe she was taken from us.'
Amelia and her five siblings are striving to keep their mum's story and morals alive.
She said: 'Mum is very much a part of our lives every day - the house is covered in pictures of her and she's brought up in every conversation we have.
'She had three morals that she always stuck to: always travel, always put family first and always see the world for the best it could be - and that's what we live by.
'She was a very charitable person also, so we all try and do our best for charity and often sit down with families who have lost their parents and share our story with them.
'Although nothing is going to bring her back, there's things we strive to do every day to keep her alive and not let this monster have the last laugh.'
A Ministry of Justice spokesman said: 'This is a tragic case and our sincere condolences are with the victim's family and friends.
'Serious further offences such as this are very rare, but each one is taken extremely seriously and investigated fully.
'A full review into this case is underway, and we will carefully consider the findings to make sure all possible lessons are learnt.'
This article has been adapted from its original source.
