At 24, Helen Hargan appeared to have the world at her feet.
She was engaged to her fiance, Carlos Gutierrez, and would soon be moving into a new home.
Her mum Pam - a successful businesswoman - had offered to buy her a house. Lucky girl.
For now though, Helen was living with her mum and her sister Megan, 34, in McLean, Virginia.
But around 11.30am on 14 July 2017, Helen called Carlos, crying hysterically.
She said something horrific had happened.
Carlos lived more than 1,000 miles away in Dallas, Texas.
There wasn’t much he could do from there.
But when he could no longer reach Helen by phone,
