Scotland’s outgoing Lord Advocate has said it is “inconceivable” that a fatal accident inquiry will not be held into the M9 crash tragedy.
Frank Mulholland QC said he would expect an inquiry to go ahead given the level of public concern.
Lamara Bell, 25, died in hospital after lying critically injured in a crashed car for three days last July, despite the accident being reported to police on the day it happened.
Her partner, John Yuill, 28, died at the scene of the accident, when their car plunged down an embankment off the M9 near Stirling.
Police Scotland only responded three days later after a follow-up call.
Mr Mulholland instructed the Police Investigations and Review Commissioner (Pirc) to carry out an independent probe into the circumstances.
Earlier this year, Scottish Liberal Democrat leader Willie Rennie wrote to the Lord Advocate asking for an update on the investigation.
In a reply to Mr Rennie, Mr Mulholland said: “When all investigations are completed this case will be reported to Crown Counsel for instruction as to what, if any, proceedings are appropriate.
“It is open to Crown Counsel to instruct fatal accident inquiries or criminal proceedings where appropriate. As with any sudden death case, the evidence in this case will be analysed carefully and all options will be considered.
“I should add that, notwithstanding a decision on criminal proceedings, I find it inconceivable that a fatal accident inquiry will not be held given the public concern over this tragedy.”
Mr Rennie said: “The Lord Advocate is absolutely right to say that there has been huge public concern over this tragedy and it is vital that the families of John Yuill and Lamara Bell get the answers they need.
“An FAI would ensure the facts of how this tragic incident unfolded are fully understood and set out clearly the urgent steps we need to take to support police control-room staff so this never happens again.”
A Crown Office spokesman said: “The Crown has received an interim report from the Pirc in connection with an incident on the M9 in July 2015.
“It would be inappropriate to comment further while the investigation is live.
“The families of those involved will continue to be kept updated in relation to any significant developments.”
Pirc is also investigating Police Scotland’s handling of a case involving the discovery of a man’s body in his flat, days after a call was made to them raising concerns about his welfare.
The body of Andrew Bow, 36, was found in his Edinburgh home on 23 March.
A neighbour called police to say she was concerned about his wellbeing, days before Mr Bow was found.