Family of Sheku Bayoh are still waiting to learn whether police officers involved in his death will be prosecuted.
Relatives of the 31-year-old Kirkcaldy man who died in police custody in 2015 challenged the ruling by Lord Advocate James Wolffe more than a year ago against pressing charges.
A review of the decision was launched, meaning officers could still face criminal charges.
Only once prosecution is ruled out will either a public inquiry or a fatal accident inquiry be held to establish the circumstances of Mr Bayoh’s death in Kirkcaldy in May 2015.
Pushing for progress, Scottish Liberal Democrat leader Willie Rennie said: “We are more than four years on from this tragedy and we still haven’t reached a conclusion on the first decision that needs to be taken, whether officers should be prosecuted.
“This must be agonising not only for the family but also the police officers.
“We know this case isn’t simple and we need to get it right but it can’t be right that it has been delayed for this long.”
Victims have a right to ask the Crown to review decisions not to prosecute.
Requests should normally be made within a month of the decision being notified and the Crown aims to complete the review within 20 working days but states that complex cases can take longer.
It is understood the Crown has been regular contact with the Bayoh family’s legal team.
A Crown Office and Procurator Fiscal Service spokesman said: “This has been a complex investigation and COPFS appreciates that it has been a difficult time for all those involved.
“Officials from COPFS have maintained contact with the legal representative of the family of Sheku Bayoh over the status of the case.
“The Crown is committed to ensuring that the facts and circumstances surrounding the death of Mr Bayoh are fully aired in an appropriate legal forum.
“In order to protect any potential proceedings and to preserve the rights of the family, the Crown will not comment further at this stage.”
Father-of-two Mr Bayoh died in the Victoria Hospital, Kirkcaldy, after being restrained by up to nine police officers who said they were responding to reports of a man acting erratically armed with a knife.
It is thought he suffocated as he lay face down with police on top of him.
The presence of drugs in his system may have contributed to his death.
