Background
As the results of an Amnesty International study of national law in more than 125 countries published in September 2001 demonstrate, international law permits any state to exercise universal jurisdiction over war crimes, crimes against humanity, genocide, torture and, indeed, even ordinary crimes, and all but a handful of the national laws providing for universal jurisdiction do not contain any requirement that the suspects be present in the country in order for the police, prosecutors or investigating judges to open a criminal investigation.
The four Geneva Conventions of 1949 (Geneva Convention I, Art. 49; Geneva
Convention II, Art. 50; Geneva Convention III, Art. 129; Geneva Convention
IV, Art. 146) permit any state party to open an investigation of grave breaches and to request the extradition of suspects without any requirement that the suspects have ever entered territory subject to that state's jurisdiction, as long as they have sufficient information concerning the possible criminal responsibility of the suspect (prima facie evidence):
"The High Contracting Parties undertake to enact any legislation necessary
to provide effective penal sanctions for persons committing, or ordering to
be committed, any of the grave breaches of the present Convention defined
in the following Article 50 (Convention I)
http://www.icrc.org/ihl.nsf/9ac284404d38ed2bc1256311002afd89/8de472a17f7e30afc12563cd0051a2d6?OpenDocument
As the results of an Amnesty International study of national law in more than 125 countries published in September 2001 demonstrate, international law permits any state to exercise universal jurisdiction over war crimes, crimes against humanity, genocide, torture and, indeed, even ordinary crimes, and all but a handful of the national laws providing for universal jurisdiction do not contain any requirement that the suspects be present in the country in order for the police, prosecutors or investigating judges to open a criminal investigation.
The four Geneva Conventions of 1949 (Geneva Convention I, Art. 49; Geneva
Convention II, Art. 50; Geneva Convention III, Art. 129; Geneva Convention
IV, Art. 146) permit any state party to open an investigation of grave breaches and to request the extradition of suspects without any requirement that the suspects have ever entered territory subject to that state's jurisdiction, as long as they have sufficient information concerning the possible criminal responsibility of the suspect (prima facie evidence):
"The High Contracting Parties undertake to enact any legislation necessary
to provide effective penal sanctions for persons committing, or ordering to
be committed, any of the grave breaches of the present Convention defined
in the following Article 50 (Convention I)
http://www.icrc.org/ihl.nsf/9ac284404d38ed2bc1256311002afd89/8de472a17f7e30afc12563cd0051a2d6?OpenDocument