Gecas, 85, who changed his name while living in exile, is charged in Lithuania with the murder of Jews in war-torn Lithuania and Belarus when he served in the pro-Nazi 12th Lithuanian Auxiliary Police Battalion.
The case has been a long time coming. Gecas was first charged in Lithuania back in 1987, when Soviet prosecutors brought a case against him. Inexplicably they dropped the case the same year, although propaganda efforts aimed at implicating more visible members of the Lithuanian exile community continued unabated.
In 1992 Gecas lost a libel case against Scottish Television, which aired a documentary implicating him in crimes against humanity during World War II.
The judge trying the case, Lord Milligan, found a preponderance of evidence in favor of affirming Gecas' guilt.
He said he was "clearly satisfied" Gecas had "participated in many operations involving the killing of innocent Soviet citizens including Jews, in particular in Belarus, during the last three months of 1941, and in committing war crimes against Soviet citizens who included old men, women and children."
Lord Milligan added: "I further hold it proved that (Gecas) was the platoon commander of the 12th Auxiliary Police Service Battalion and that that platoon participated specifically in six operations."
"It inevitably follows that he committed war crimes against innocent civilians of all ages and both sexes in the course of these operations," Milligan wrote.
During the case, Gecas maintained throughout that he committed no war crimes and killed no one.
In a 1995 question time in the British Parliament, an MP asked then Prime Minister John Major during what period of time Antanas Gecas was employed by British intelligence.
"It remains the government's policy not to provide information on operations at the security and intelligence agencies," Major replied.
There are reports that around 30 members of Lithuania's 12th Auxiliary Police Battalion have lived in Britain during the last decade.
According to the Press Association, members of the British Crown Office's war crimes commission, including Scottish jurists who investigated the Gecas case, visited Vilnius in 1992 and collected evidence. During depositions some former auxiliary police battalion officers confirmed that Lithuanians had shot civilians, and that it was not solely the work of the Germans.
The issue of Gecas' intelligence connections surfaced again in Lithuania's current bid to have him extradited to face charges in his homeland. The newspaper The Scotsman ran an article last week on the ongoing attempt to extradite Gecas, who is currently in hospital.
The Scotsman reported Gecas' unit was one of the most feared Nazi death squads during World War II, and in one operation in Slutsk around 1,000 Jews were dragged from their homes and workplaces, shot and buried.
The paper erroneously reports that Gecas then moved into Belarus (Slutsk is just south of Minsk). When the balance of power shifted, he enlisted with Polish forces there.
The paper reports he was awarded both the German Iron Cross and the Polish Military Medal.
"Gecas' reinvention as a mining engineer in Scotland is said to have been aided by his recruitment as a spy for the British Secret Intelligence Service and Special Branch. The links are so sensitive that they will never be acknowledged publicly and only a handful of government ministers at the time knew of them," The Scotsman reported.
Nazi hunters from the Simon Wiesenthal Center in Jerusalem said Gecas' extradition might have been delayed because of British reluctance to give up one of their agents.
Whatever role Gecas might have played in British intelligence, he was sent to the mines. Literally. In 1947 the National Coal Board took him on and sent him to work in the pits near Newcraighall and Bilstonglen in Scotland.
Gecas didn't neglect his education during his stint in the mines. He studied mining engineering and management at Heriot Watt University in Edinburgh, slowly pulling himself up in the industry. In 1959 he was granted British citizenship. Later, he married a young nurse named Astrid.
The Scotsman reported he became a useful contact for the intelligence services in the mines, which were full of Eastern European immigrants of unknown political loyalty.
He also helped the police and intelligence agencies during the miners' strike of 1973, by allegedly turning over the names of the strike's main union agitators.
Gecas retired from the National Coal Board in 1981, but within five years came under scrutiny when the Simon Wiesenthal Center presented a list of Nazi collaborators sheltering in Britain to the authorities.
That first revelation was soon followed by the Scottish Television documentary, widely viewed in Great Britain.
Speculation that Gecas curried the favor of the British intelligence community was only fueled by a decision reached by Britain's Special War Crimes Unit, which found insufficient evidence to prosecute.
Gecas suffered a cardiac stroke in May this year and was hospitalized. His lawyer Nigel Duncan said there will not be any movement on the extradition request until Gecas' health condition is checked again, leading some to believe he might elude trial by claiming infirmity, as have a number of previous suspects in Lithuanian genocide trials.
Earlier there was speculation the Gecas' team might argue against extradition by citing the amount of time that has passed since the events he is alleged to have committed, and the lack of clear evidence. The Scottish executive responded to that argument by asking Lithuania to divulge whatever new evidence it had on Gecas, a request the Lithuanian prosecutor general complied with.
Duncan also hinted at a possible challenge under the Human Rights Act by claiming his client could not receive a fair trial in Lithuania.
Whatever the outcome of the case, it promises to set a precedent. The defendant, decorated by two hostile armies during World War II, initially charged in a Soviet case that conveniently evaporated - and allegedly a British agent the MI5 saw fit to send to the mines of Scotland - probably could not expect a fair trial in any country but Lithuania, which technically ceased to exist at the time he is said to have committed the atrocities.
The Lithuanian prosecutor general is currently investigating about 90 cases of genocide committed against Lithuanian citizens. Some 15 have gone to trial, but independent Lithuania has yet to make a single conviction for collaboration with the Nazis and genocide against Jews and other ethnic minorities.