A couple who lost their teenage daughter in the Glasgow bin lorry crash have said "we need answers" ahead of an inquiry into the tragedy next month.
Matthew and Jacqueline McQuade spoke out almost six months after a runaway council truck killed 18-year-old Erin and Mrs McQuade's parents, Jack and Lorraine Sweeney.
A fatal accident inquiry (FAI) looking at the circumstances of the crash, in which three other people also died, will begin at Glasgow Sheriff Court on July 22.
The court will hear about the lorry driver's medical background and his fitness to hold a licence prior to the accident three days before Christmas.
Mr McQuade, 50, said victims' families needed to know what caused the crash and whether it could have been avoided.
He told the Scottish Sun: "If my daughter had been murdered, there wouldn't have been a stone left unturned.
"This fatal accident inquiry and the way it is handled is now the most important thing to us.
"We feel that the investigation should have lasted longer. We need the truth and we need answers."
His 44-year-old wife told the paper she feared the inquiry was being held to "appease the public" and "we'll just have to accept the outcome because nothing will make any difference".
Sheriff John Beckett QC will oversee the FAI, which will also examine technical evidence relating to the bin lorry and whether it was appropriate that it took the route it did through Glasgow city centre on December 22.
He was appointed to replace Sheriff Principal Craig Scott who withdrew last month after realising that he knew one of the victims.
Miss McQuade and her grandparents Jack, 68, and Lorraine, 69, all from Dumbarton, West Dunbartonshire, died when the truck lost control in Queen Street.
Stephenie Tait, 29, and Jacqueline Morton, 51, both from Glasgow, and Gillian Ewing, 52, from Edinburgh, were also killed when the vehicle mounted the pavement before crashing into the side of the Millennium Hotel in George Square.
In the newspaper interview the McQuades criticised a Crown employee's "insensitive" approach towards the family during a meeting to discuss the investigation.
The inquiry is being led by Solicitor General Lesley Thomson, Scotland's second most senior legal officer.
A Crown Office spokesman said: "We appreciate how terribly devastating this incident has been on all the families involved and we assure them that we are doing everything possible to ensure that the forthcoming fatal accident inquiry, led by the Solicitor General, will provide them with the answers they deserve."
On the family's reported criticism of a Crown employee, the spokesman said the experienced staff member had never used offensive or unacceptable language at any time.