'We do believe it's highly likely that a number of people knew what happened to her' - Grieving parents of Melanie Hall
The parents of Melanie Hall have pleaded for those with information to come forward on the 20th anniversary of her disappearance.
Steve and Pat Hall first realised there was a "major problem" when their daughter failed to show up for work on the morning of June 10 in 1996.
University graduate Miss Hall had gone to a nightclub with her boyfriend on the Saturday night but became separated from him there.
Her remains were discovered in vegetation next to the junction 14 northbound slipway of the M5 in Thornbury on October 5 2009.
"We're saying once again: someone out there knows something, someone could come forward with information which could solve this crime," Mr Hall said.
"For whatever reason they've not done so and we would implore them to find the moral fibre to do that and assist with this investigation.
"I believe there are a number of people out there who probably know what happened to Melanie and the people involved and for whatever reason they've seen fit not to come forward."
Mr Hall said his daughter's murder had left "a number of victims" including himself, his wife, his daughter and his 97-year-old mother.
"Our lives have been totally altered and they can't be put back together completely," he added.
Miss Hall was spending the weekend with her boyfriend, a doctor, and went to a barbecue with colleagues on the night of June 8 before going to the nightclub.
Being alone at the nightclub after becoming separated from her boyfriend would have been "alien territory" to Miss Hall, her parents say.
"What she did then, I don't know and no one else knows at the moment other than the people who were involved in her demise," Mr Hall said.
"She would have just melted into the crowd, she was young, she was 25, she was blonde. I suspect there were a lot of young blonde 25-year-old girls there.
"In semi-darkness some people might have seen her, there were a few reports of seeing her around the side of the dance floor and that's all people have been able to remember.
"The crux of the thing is we're looking to what happened afterwards and what people know about the person or persons who killed Melanie.
"We do believe it is highly likely that a number of people knew what happened to her."
Mr Hall said it is possible those with information about Miss Hall may be scared to come forward.
"But loyalties do change," he said.
"People die, fear becomes removed, people are betrayed and people look for reprisals, so we're hoping that somewhere down the line there is a change of circumstances and that people who have the information will come forward."
Miss Hall's parents were not "unduly concerned" when their daughter failed to return from the nightclub and believed she may have been staying with her boyfriend.
"It wasn't until Pat got to work on Monday morning and one or two colleagues of Melanie rang Pat to say 'well she's not turned up for work, is she not well?'," Mr Hall said.
"By Monday night we realised that no one knew where she was. She certainly wasn't a girl that would have left home, she was really enjoying life, being at home.
"We very quickly realised we had a major problem.
"I think within days we realised she was probably dead or in serious trouble in some sort of kidnap. That happened early on."
Mrs Hall said the discovery of her daughter's remains on the motorway slipway did not "make any difference" to her belief that her daughter was dead.
"It was just the fact that she had been found and left in such a public place with no dignity," Mrs Hall said.
"At least that allowed us to do that very last thing that a lot of us do for our loved ones, to actually be able to say goodbye in a dignified way."
Mr Hall has "very little feeling" towards those responsible for his daughter's death.
"Am I angry? Yes I'm angry. Would I like to see the demise of the person who killed Melanie? Yes I would. Would I forgive them? No I wouldn't, I wouldn't feel any better," he said.
"The thing that I want and Pat wants is often lost on these occasions, I actually want Melanie back and I can't achieve that, we can't achieve that. So we're never going to get closure."
The couple feel a "responsibility" to find who killed their daughter and bring them to justice.
"It is the last act that we can carry out for her," Mr Hall said.