Ms Bell, 25, was found injured at the side of the motorway three days after a car accident near Stirling that killed her partner John Yuill, 28.
The mother of two died later in hospital and it emerged that a phone call to police reporting a vehicle off the road on July 5 was not followed up.
The Lord Advocate is considering the findings of an independent report before deciding if any action, such as a fatal accident inquiry, should follow.
Ms Bell’s mother Diane, 49, has told how she stayed at her daughter’s bedside and willed her to stay alive for the sake of her children Alysha, ten, and Kieran, six.
Ms Bell had suffered a brain injury, broken limb and severe dehydration.
The grandmother told the Scottish Sun: “To look at her, she just had wee cuts and marks on her and a broken arm. She just looked like our girl.
“I kept saying ‘Mara, wake up. I’m here’. But she didn’t. I would say ‘You need to come home - the kids need you’.”
The couple had been camping in Lochearnhead, Stirlingshire, when their Renault Clio came off the road.
Ms Bell’s brother Liam raised the alarm when he could not contact them and police launched a missing person appeal.
Their car was not found until three days later and the Police Investigations and Review Commissioner (Pirc) was tasked with examining why a call reporting a car off the road was not logged and acted upon.
Ms Bell’s mother said: “I used to see or speak to her every day. I miss her so much.
“I still expect her to call or text or bounce through the front door - I can’t believe she’s gone. The past year has been torture.
“We want to know why it took so long for anyone to tell us what had happened.”