An Edinburgh mother trying to find out what happened to her dead baby's body has written to Police Scotland and the Crown Office to ask if any criminal charges are likely to be brought.
Lydia Reid's son's coffin contained no remains when it was removed from its burial plot two months ago.
A police inquiry was launched but she said there was a "lack of progress".
The Crown Office said it would be inappropriate to comment during the investigation.
Ms Reid's son Gary died at seven days old in Edinburgh's Hospital for Sick Children in July 1975.
Earlier this year, the 68-year-old was granted a court order for an exhumation to be carried out at the burial plot but no human remains were found.
The exhumation was conducted by respected forensic anthropologist Prof Dame Sue Black.
She found a shawl, a hat, a cross and a name tag in the plot at Saughton Cemetery in Edinburgh, as well as the disintegrated coffin.
Her report concluded that the coffin was buried without human remains.
After details of Prof Black's report emerged, Police Scotland said detectives were trying to establish if any criminality had occurred.
Both NHS Lothian and Scotmid Funerals said they were giving their full co-operation.