Leon Briggs, 39, died in November 2013 after he became ill following his detention at Luton Police Station.
On February 20, the Independent Office for Police Conduct (IOPC) removed its direction for the misconduct hearing after a series of objections were raised by Bedfordshire Police.
The Crown Prosecution Service (CPS) also chose not to prosecute in September 2018. With the collapse of the misconduct hearing, the officers will face no further action.
Leon Briggs’ mother, Margaret, said: “As a family we are devastated and outraged at this decision. We have spent the last three weeks in a state of limbo waiting for the hearing to start.
We cannot understand why the issues raised at this stage were not dealt with earlier. It is over six years since my son’s death and to be told that the officers will not face any public scrutiny is further denial of justice and accountability for Leon.”
Bedfordshire Police were at loggerheads with the IOPC over the misconduct hearing, accusing the watchdog of leading a flawed investigation. Meanwhile the IOPC criticised Beds Police’s refusal to offer evidence against the officers.
On February 17, the force requested the IOPC withdraw its directions for the hearing.
With no evidence for the panel to consider and further delays potentially taking the hearing into 2021, the IOPC stated it “reluctantly”
An IOPC spokesman said: “Leon Briggs’ family have waited many years for the actions of the police officers involved to be scrutinised in public.
“The last minute actions of Bedfordshire Police and the most recent delays mean that his family have been denied that right.
“Bedfordshire Police’s announcement earlier this week that it would offer no evidence to its disciplinary panel means that the hearing had no prospect of proceeding.”
Assistant chief constable of Beds Police, Jackie Sebire said: “The force has always wanted a fair and transparent hearing to provide answers to the family of Mr Briggs and provide confidence to the public.
"However, we became aware during the initial legal arguments of failings in the independent investigation which called into question the proportionality, fairness and the public interest in continuing with this hearing.
“Those concerns, coupled with the likelihood of yet further delay to proceedings, which have already gone on for an unacceptable length of time, meant we were left with little option but to ask the IOPC to review its decision over directing the hearing.
“We must be mindful that there is still an inquest due to be held, however it is important to stress that none of the officers involved in this hearing were accused of causing or contributing towards Mr Briggs’ death.”