The accused, a 54-year-old Swedish citizen, lives in central Sweden. According to prosecutors he participated in massacres in west Rwanda during the 1994 genocide. He could be responsible for the deaths of thousands.
"We have a responsibility to ensure that Sweden is not a haven for suspected war criminals and for those who commit genocide," said prosecutor Magnus Elving.
Rwanda had asked for the man's extradition, but prosecutors said Sweden could not comply since he received Swedish citizenship in 2008.
For three weeks in November to December 2012 the trial will transfer to Rwanda where witnesses will be heard in the high court of Kigali, the Rwandan capital. For practical reasons it was not possible to bring some of the witnesses to Sweden.
According to Elving it will be a standard, Swedish trial taking place at a foreign location.
The suspect will not travel to Rwanda but will participate in the trial via a video feed. The prosecution alone will call 40 witnesses.
"There are very strong reasons for carrying out these processes even if it is very costly," said Elving.
Elving said that the 54-year-old Swedish citizen could have been involved in massacres at four different locations in Rwanda.
The 54-year-old denies the charges. His lawyer, Tomas Nilsson, has questioned the validity of the evidence against his client, saying it is unreliable particularly since it concerns events that took place 18 years ago.
The massacre of Tutsis in Rwanda began in April 1994. Over the course of approximately 100 days, an estimated 800,000 people died.
The trial commences in Sweden on November 16th 2012.