Thai authorities have convicted two bar workers for the murders of the British backpackers, amid allegations that the suspects made confessions under duress.
Mr Miller and Miss Witheridge were brutally murdered on the holiday island of Koh Tao in September.
Zaw Lin and Wai Phyo have been sentenced to death.
The mother of murdered Jerseyman David Miller has described the anguish of hearing the details of her son's death at an inquest today.
Sue Miller has said she had the feeling of "attending her son's funeral all over again".
At the inquest today, Sue and her husband Ian Miller cried as they listened to the details of their son's murder.
The purpose of today's meeting was to conclude the inquest which began shortly after David's death in September 2014.
Mrs Miller took the opportunity to provide the inquest with a victim impact statement in which she described the effect her son's murder has had on the family.
Recalling the day she learned of David's death, Sue Miller said she heard a radio report at around 11am which announced two deaths on the Thai island of Koh Tao, and said she just knew one of them was David.
Her worst fears were confirmed when police arrived at her home to deliver the terrible news a short time later.
She said grief and shock have enveloped the family, and the year that immediately followed had been unbelievably difficult, as the Millers struggled to manage things no family should ever have to.
Sue Miller said the pain of losing David was enduring, that he had been so loved by everyone.
She added that she misses his stories, his energy, his zest for life, and described him as a real people person with a clear sense of justice.
She said that as a result of his murder the family will always have a gaping hole in their lives.
Sue and Ian Miller were visibly upset as the statement was read by the coroner.
David Miller from Jersey, and Hannah Witheridge from Norfolk were found dead on a beach in Thailand in September 2014.
The Miller have told ITV News they are against the death penalty issued to the two men convicted of David's murder. The pair are appealing.
A human rights activist defending the men found guilty of murdering David Miller says the 'botched' investigation can't prove their guilt.