Allan Marshall, 30, was being held on remand at HMP Edinburgh in March 2015 when he suffered a cardiac arrest during a lengthy struggle with staff.
During the struggle, he was dragged face down and feet first by prison officers.
A sheriff said his death was “entirely preventable” at a Fatal Accident Inquiry.
Sheriff Gordon Liddle said the evidence of guards involved in Mr Marshall’s death was “mutually and consistently dishonest”.
His family are still seeking answers and recently met with Scottish Labour’s justice spokeswoman, Pauline McNeill.
Ms McNeill said: “Mr Marshall’s family and the Scottish public deserve answers over the death in custody of Allan Marshall.
“The Fatal Accident Inquiry into his death raised many troubling issues and left serious questions unanswered.
“Allan’s family has been campaigning for those answers and they must get them.
“That Mr Marshall’s family have been denied clear answers over how and why he died is simply shocking and is an indictment on the relevant authorities.
“Only a public inquiry can answer the questions on Allan Marshall’s death, re-establish transparency in our criminal justice system and provide justice for his family.”
In November 2019, the Scottish Government commissioned a review into how prison deaths are handled, with a report due to be published shortly.
The review is being led by Wendy Sinclair-Gieben, Her Majesty’s Chief Inspector of Prisons for Scotland, and is examining practices within the Scottish Prisoner Service and the NHS.
A Scottish Government spokesperson said: “Our thoughts remain with the family of Allan Marshall and the former Justice Secretary expressed his condolences to them personally when he met them.
“The safe treatment and mental health of all those in custody is a key priority for Scotland’s prisons, which care for people with higher levels of risk and vulnerability than the general population as a whole.
“We are determined any lessons that need to be learned will be learned, and that all appropriate agencies must look closely at the outcome of Fatal Accident Inquiries. Whether a recommendation is made at the end of an FAI is a matter for the Sheriff who has heard the evidence presented.
“We have commissioned Her Majesty’s Chief Inspector of Prisons for Scotland, along with a representative or families of prisoners and a human rights expert, to undertake an independent review of deaths in custody. We will consider any recommendations from the independent review carefully, when it reports later this year.”