NATO spokesman Derek Chappell confirmed that "certain material" had been seized and that it would be analysed, but he would not comment on its content.
Chappell explained that NATO possessed information that Aleksandar Karadzic and Sonja Karadzic Jovicevic were part of the network supporting war crimes indictees wanted by the UN war crimes tribunal in The Hague, notably Radovan Karadzic.
The Karadzic family owns two flats and a house in Pale. The house is used mostly by Karadzic's wife Ljiljana, but this time it was not searched although in the past it was often raided by international troops in the country.
Today's operation was carried out by several dozen NATO soldiers and local police officers.
The Hague tribunal is still looking for six fugitives, of whom four are indicted for crimes in Bosnia-Herzegovina, while Goran Hadzic and Vlastimir Djordjevic are charged with crimes in Croatia and Kosovo respectively.