Politicians have called for an inquiry into the dramatic collapse of the World's End murder trial.
Convicted killer and sex offender Angus Sinclair was accused of murdering 17-year-olds Christine Eadie and Helen Scott in Edinburgh 30 years ago.
Judge Lord Clarke said the Crown had insufficient evidence to proceed.
Questions have been raised as to why certain evidence was never heard. The Crown Office insisted there had been enough to indict Sinclair.
Independent MSP Margo MacDonald has lodged a question with Scotland's First Minister Alex Salmond, asking whether an inquiry will be heard into the collapse of the case and Sinclair's acquittal.
Labour's justice spokeswoman in Scotland Margaret Curran MSP said it was "deeply disappointing" the trial had been thrown out while her Tory counterpart, Bill Aitken MSP, added that it was right that questions would be asked in the days to come.
The teenagers were last seen in the World's End pub and their bodies dumped in East Lothian in October 1977.
Helen Scott and Christine Eadie were murdered in 1977
Sinclair had a string of convictions for sexual offences including the sexual assault and strangulation of eight-year-old Catherine Reehill in 1961.
He lodged a special defence at the World's End trial, incriminating his brother-in-law Gordon Hamilton, who is dead.
Sinclair also claimed that any sexual contact between him and the young women was consensual.
Ms Eadie's naked body was found at Gosford Bay, East Lothian, on 16 October, 1977.
Ms Scott's partly clothed body was found a few miles away in a field by the Huntingdon to Coates road, near Haddington.
After 10 days of evidence, Sinclair's defence team lodged a submission on Friday that there was no case to answer.
Lothian and Borders Police said on Monday they were "disappointed" at the decision.