The number of deaths at Scottish jails are "nothing short of a massacre", according to the parents of a student who took her own life while behind bars.
Katie Allan, who was jailed in March 2018 aged 20 for a hit-and-run while drunk, killed herself at HMYOI Polmont after being tormented by other inmates, her parents said.
After investigating deaths inside Scottish prisons, Katie's parents have said the country effectively "has a death penalty" due to the lack of mental health support and inaction to protect prisoners.
Speaking at the Scottish Parliament a year after their late daughter was jailed, Linda and Stuart Allan called for action to tackle what she described as "a genocide behind the doors of the cells".
The family, with the help of Glasgow University, where Mrs Allan is an honorary clinical professor, studied prison deaths from 2008 up to December 2018.
Mrs Allan, who worked as a nurse registrar in the NHS before her daughter's death, said: "Our campaign attempts to present to government ministers, academics and society the stark reality of what is going on in the halls of our prisons - no gloss over, no excuses, no spin, no soundbites - and ask for honest consideration.
"What we have discovered is that Scotland has a death penalty - it is no longer a jostling public spectacle around the gallows, it is a hidden and visible genocide behind the doors of the cells of our prison estate."
Mr Allan, a data inputter at a telecommunications company, described the "horrific statistics" they found by looking into the 258 prisoner deaths over the last decade as "nothing short of a massacre".
He said: "In 2008, 35% of prisoner deaths were from suicides but in 2016, 2017 and 2018 this has rocketed to over 50%, with the volume of prison deaths increasing in that time."
"Forty per cent - so that's 32 of the 82 deaths in prison - who have taken their own life were under the age of 30.
"Twelve of those 32 had taken their own life within one week of being in prison."
He added: "Sixty-seven families await a fatal accident inquiry (FAI) to be completed on their loved one - some of those are going back as far as prisoner deaths from 2014."
The family's lawyer Aamer Anwar said the Allans had lost faith in the Scottish Prison Service, "which appears more interested in spin and cover-ups".
"They believe an FAI system - held on average now two years after a suicide - is not fit for purpose, it is set up to fail families and hide what is truly happening," he said.
"The SPS treats prison suicides as hidden dirty secrets but there is nothing inevitable about suicides.
"Over half of those imprisoned today in Scotland's prisons have definable mental health problems and prison is not fit for purpose for dealing with them.
"Katie Allan and many others were failed by a system which keeps repeating the same mistakes."
After listening to Mr and Mrs Allan, Labour's shadow justice minister Pauline McNeil said: "What I heard this morning was that the Scottish Government needs to take urgent action around young offenders and mental health in prisons.
"And to hear that 67 grieving families still don't know how their loved one died - what sort of country are we living in? It can't continue like this."
Lib Dem justice spokesman Liam McArthur said: "The justice system has failed family after family.
"It has been two years since the Scottish Government accepted Scottish Liberal Democrat proposals to expand the mental health workforce in prisons.
"However, so far there are just two new staff across Scotland's 15 prisons."
Calling for an independent review into the "bureaucratic and broken" FAI system, Mr McArthur added: "No more families should have to face agonising waits of up to a decade for answers about their loved ones' deaths or be asked to make a financial contribution towards this process.
"Families can't have closure and the justice system can't learn lessons, putting more lives in danger."
A Scottish Prison Service spokesman said its thoughts were with the friends and family of Miss Allan.
He said it is awaiting the FAI into her death and a report from the Chief Inspector of Prisons with any recommendations for changes to be made.