A Swedish investigation team led by chief international prosecutor Tomas Lindstrand, Stockholm, arrived in Indonesia on Monday.
They are in Indonesia to investigate alleged links to crime and acts of terror between Swedish GAM residents and GAM members and supporters in Indonesia.
Tomas Lindstrand launched a preliminary investigation last month against GAM leaders in Sweden. The visit to Indonesia is a crucial part of the investigation.
The team travels to the war torn Aceh province on Wednesday, reports Indonesian media, and will stay there until Sunday.
Indonesia has promised to give the Swedish team full access to imprisoned GAM members in Aceh and, according to local media reports, also allowed the guests to visit conflict areas on their own risk.
GAM wants to make Aceh a free nation. After a brief round of peace talks last year fighting broke out again and the intensity of this war has increased ever since.
The Swedish team declined any comments to the press immediately before the journey, which dates were kept secret by Stockholm until sources in Indonesia brought the silence on Tuesday.