Sperisen, 43, holds both Swiss and Guatemalan citizenship and therefore cannot be extradited from Switzerland to stand trial in his homeland.
   
But under Swiss law, any citizen of the Alpine country can be tried at home for alleged crimes committed abroad.
   
Sperisen is accused of involvement in the summary execution and subsequent cover-up of the murder of seven inmates in a jail in 2006, and of three escaped prisoners in 2005.
   
Geneva prosecutors charge that he personally shot one of the 2006 victims.
   
Sperisen denies the charges, which could carry a life sentence.
   
Appointed police chief in 2004, he left Guatemala in 2007 amid a scandal that saw him and the country's interior minister Carlos Vielmann resign that March, two weeks after the murder of three members of parliament from El Salvador.
   
Sperisen's paternal grandfather was a Swiss immigrant to Guatemala, giving him the right to Swiss citizenship.
   
His father is Guatemala's ambassador to the World Trade Organization, which is based in Geneva, and Sperisen was arrested in the city in August 2012.
   
He has been in jail since then, with Geneva justice authorities saying there is too great a risk that he will flee Switzerland if he is released on bail.
   
The trial is expected to last three weeks.
   
A Frenchman who was detained in the prison where the 2006 killings took place is scheduled to take the witness stand next Wednesday.
   
Sperisen's former right-hand man, Javier Figueroa, has reportedly also been called as a witness.
   
Figueroa was prosecuted by Austrian justice authorities on similar charges, and acquitted in 2013.
   
Former interior minister Vielmann, who holds dual Guatemalan and Spanish citizenship, now lives in Spain and is due to be tried by a court there over the prisoner killings.