Police Scotland has spent six years examining whether planes used Scottish airports to transport terror suspects to be tortured or held at Guantanamo Bay.
But they were denied crucial evidence by the US Government after it refused to share classified information on the rendition and ‘enhanced interrogation’ programme operated by the George W Bush administration.
A 2014 report by American senators helped lift the lid on the programme run by the US foreign intelligence agency, which saw terrorist suspects transported around the world to secret ‘black sites’ to be interrogated and tortured.
Prisoners were subjected to physical abuse, sleep deprivation, waterboarding and mock executions. At least one detainee is reported to have been killed by interrogators, while another lost an eye.
However, only a partially-classified 525-page portion of the 6,000-page Senate Intelligence Committee report has been published, meaning details of the rendition programme remain secret.
In 2013, the then-Lord Advocate Frank Mulholland ordered an investigation after it emerged jets operated by the CIA that stopped at Scottish airports may have been carrying detainees in breach of UK laws against torture.
As many as 21 CIA flights are suspected of having landed in Scotland at Glasgow, Prestwick, Wick, Inverness and Aberdeen airports.
Police Scotland requested access to the full, unredacted Senate report, but were denied by US intelligence authorities. Lord Advocate James Wolffe last year described the investigation as “complex and challenging ... with evidence having to be sought and obtained from countries outwith the United Kingdom”. The Crown Office is now examining whether any criminal charges can be brought.
SNP defence spokesman Stewart McDonald said it was of the “utmost seriousness” the Prime Minister raise the issue with the president before he leaves the UK.
“It’s vital that Scotland’s law enforcement bodies are able to get to the bottom of their investigations and determine if criminality has occurred,” he said.
“In these circumstances, the UK Government should be pulling out all the stops to ensure that they have all the resources needed, including those held by officials in the US Government.
“This is of the utmost seriousness. The Prime Minister must show in these last few weeks of her premiership that she is not afraid to stand up for the rule of law to a bullish president.
“If she hasn’t already done so, then she needs to press this home with President Trump himself before he departs UK soil.” Police Scotland Detective Superintendent Faroque Hussain said: “Specialist officers from Police Scotland’s Organised Crime and Counter Terrorism Unit have gathered and analysed all the information made available to them and have submitted a report, which is being considered by the Crown Office.”
The Crown Office said findings from Police Scotland investigators was being considered. “As this is a live investigation, it would not be appropriate to comment further,” a spokeswoman said.