Life number one was from 1916 to 1939, which saw him develop from schoolboy to successful student, later becoming a popular Lithuanian air force cadet.
Juozas Sarka, 80, remembers him at school, and when he heard he was in Vilnius, turned up at the courtroom there to see if it could be the same man. Mr Sarka knew about KGB trials, and faked evidence - he had been a doctor until 1940, and was exiled for six years to Siberia - and wanted to see if that was what the British were doing to the Antanas Gecevicius he had known more than 50 years earlier.
The young Gecevicius was not a bully, Mr Sarka remembers, not even a leader, but a conscientious if not outstanding student. 'He used to say prayers every morning at grammar school. It's hard to believe such a man as I knew could kill innocent children and women,' he said.
The second Mr Gecevicius - the one he now denies existed - came into being in the war. Lithuania had been briefly independent since 1919, but under the Nazi-Soviet pact the Soviet Union moved in. Then, in 1941, the Germans broke the pact, and in their eastward sweep into the Soviet Union annexed Lithuania.
Morality and nationality for all Lithuanians became complex and relative. Gecas joined a Lithuanian police battalion as a lieutenant in charge of a platoon. The 12th battalion was used by the Germans to kill thousands of Lithuanian Jews - taken from ghettos in cities and from small towns and villages to be shot. By autumn 1941, when there were few Jews left in Lithuania, the battalion and others were taken by the Germans to do a similar job in German-occupied Byelorussia (now Belarus).
Juzas Aleksynas, speaking in 1987 during the disputed STV programme, said that while the unit was shooting Jews, he had seen Gecas, his commanding officer, use his revolver to 'finish off' victims who were still alive. This was the only major allegation not proved by STV.
Later, Mr Gecas won an Iron Cross fighting for the Germans against Soviet partisans, as the Lithuanians were moved westwards. By 1944 they were being used to prop up the line against the Allied advance through Italy.
In September 1944, Mr Gecas's company was captured by the United States Army.
He had defected either to be on the winning side or because he had joined the Germans to fight Russians, and now found himself hundreds of miles away fighting the Allies.
From November 1944 to September 1946 he served in Italy with the Free Polish Army, and was again decorated for bravery. He entered Britain in 1946 with the Polish Resettlement Corps. Whatever his motives for swapping sides, it had presented him with an easy means of laundering his past, and a clean sheet for a new life in Britain. Having fought with the Polish Commando under Polish officers, no one took the trouble to look for war criminals - the Poles had been victims of the Nazis, not among the perpetrators of war crimes.
By 1956 he was a full British citizen. His neighbours in Edinburgh - a Jewish family - were amazed when he was named as a suspected war criminal in 1986.
Unlike many emigres, Gecas had not lived in an emigre community, but had 'Scotticised' his life, giving his children British names. He was a model citizen, worked for the National Coal Board, and retired in 1981.
His wife is Sri Lankan. They married in 1959 when he was 43 and she a 19-year-old nurse. She told the court that he had never talked about the war because 'he wanted to spare the young people those horrors'. He had never told her quite what personal horrors he meant.