Mrs Elliott said, although they were there, neither she nor Sophie saw them.
"I didn't like the way he treated her and I used to say 'Sophie you don't have to put up with this'. She said "I know mum, I know'.
Weatherston had begun psychologically abusing Sophie within the first three weeks of their relationship.
"He didn't physically abuse her until the end ... I guess that's why we missed it. If it starts early, it won't ever change."
She also referred to several women who had approached her since Sophie's death admitting "that's exactly what I went through". The presentation, entitled Love Shouldn't Hurt, also included a 20-minute film featuring interviews of Sophie's closest friends.
The talk came within weeks of Jesse John Ferris-Bromley beginning a prison sentence for the murder of Massey University student Virginia Ford.
Mrs Elliott was also joined by ex-policeman Bill O'Brien who co-wrote the book Sophie's Legacy.
HOW TO GET HELP
If you are in immediate danger please call 111. For help or more information please call these helplines:
Women's Refuge free national crisisline operates 24/7 0800 REFUGE or 0800 733 843 www.womensrefuge.org.nz.
Shine, free national helpline 9am - 11pm every day 0508 744 633 www.2shine.org.nz.
It's Not Ok: Information line 0800 456 450 www.areyouok.org.nz.
Manawatu Abuse Intervention Network (06) 354-5355 or 027 356 1701.