A Fatal Accident Inquiry (FAI) into a helicopter crash that claimed four lives in 2013 should be held "without any further delay", an MSP has said.
George Allison, Sarah Darnley, Duncan Munro and Gary McCrossan died and 14 others were rescued when the Super Puma aircraft crashed two miles from Sumburgh Airport, Shetland.
The helicopter was transferring oil workers at the time.
Shetland MSP Tavish Scott said the Air Accidents Investigation Branch and Police Scotland investigations have finished but a date is yet to be set for a mandatory FAI.
The Liberal Democrat MSP is now calling on the Crown Office to move ahead with an FAI and passed a parliamentary motion on the issue.
Mr Scott said: "I want the Crown Office to ensure the earliest possible holding of the FAI into the circumstances surrounding the helicopter crash at Sumburgh in 2013.
"Four years after the tragedy, families still wait for closure.
"At the time of the 2013 crash, the families were assured that they would not wait for many years for an FAI. Yet it took five years after the 2009 North Sea helicopter crash with 16 fatalities for an FAI to be held.
"Police Scotland, at that time, promised families of the 2013 crash that they would not have to endure such a lengthy wait for answers. Unfortunately they did.
"A considerable period has now passed following the Sumburgh crash and families are still no nearer knowing what happened and why. Everyone involved would want this FAI to be held without any further delay."