In 2013, an academic study presented fresh evidence Scottish airports were used in the extraordinary rendition of terror suspects by the CIA in the years after 9/11.
Researchers Dr Ruth Blakeley, of the University of Kent, and Dr Sam Raphael, of Kingston University in London, said 13 flights with links to the programme had landed at Aberdeen, Inverness and Wick airports.
The use of Edinburgh, Glasgow and Prestwick had previously been identified by researchers as part of an online database charting the movement of suspects overseas for interrogation and alleged torture.
The academics’ research led Police Scotland to start its own investigation which remains ongoing nearly four years later.
In the febrile atmosphere of Donald Trump’s early days in the White House, the issue of torture has once again come to the fore.
Perhaps unsurprisingly, the new president is a fan of what is sometimes euphemistically referred to as “enhanced interrogation”, refusing even to baulk at the simulated drowning technique known as waterboarding.
But he is not the first Commander in Chief to condone such practices.
A 2014 redacted US Senate report accused the CIA of inflicting pain and suffering on prisoners beyond legal limits and overplaying the effectiveness of the techniques in thwarting terror attacks.
At around 6,000 pages long it was hoped the full unredacted document would shed light on the rendition programme and Scotland’s alleged role. The Crown Office certainly thought so, instructing Police Scotland to seek a copy in late 2014.
More than three years on, both the prosecution service and the police remain coy on the issue, refusing to reveal whether the Americans ever released the information they sought.
The academic research into rendition never managed to establish whether prisoners were on board any of the aircraft which stopped in Scotland.
As of last year, Police Scotland’s investigation had found no evidence of that either. But regardless of whether terror suspects were on the flights, Scottish airports should never have been used to help facilitate acts the United States knew it could not carry out on home soil.
If the CIA and other agencies stopped off in Scotland it is unlikely they did so without the knowledge of the UK Government.
At the weekend the human rights charity Reprieve accused the Scottish Government of “alarming indifference” on the issue after it refused to intervene to expedite Police Scotland attempts to secure the Senate report.
Scottish ministers are undeniably between a rock and a hard place.
The Scottish Government has repeatedly expressed its opposition to torture, yet may have inadvertently been party to rendition even if, as is likely, it had no knowledge of the CIA flights.
Sixteen years on from 9/11 and fourteen from the start of the Iraq war, we still don’t fully understand what part Scotland played in the War on Terror.
As the alleged crimes of the Bush era recede further from view, the world is now faced with a new US regime seemingly happy to once again embrace the use of torture.
Before Scotland can speak out with any credibility against the crimes of the here and now, we need to know our involvement in the injustices of the past.