Plainclothes NATO troops have arrested a man suspected of assisting Bosnian Serb war crimes fugitive Radovan Karadzic.
Mr Zeljko Jankovic, known as Luna, was seized while taking his children to school, local media said.
The arrest in Biljelina city centre was based on information gained when troops carried out four days of searches in Karadzic's wartime stronghold at Pale, near Sarajevo.
Mr Jankovic is the second alleged member of what the NATO Stabilisation Force (SFOR) calls the Karadzic "support network" to be arrested this month.
Both men belonged to a Serb Republic special police unit and both are linked in media reports with the murder of a former deputy police chief in Pale in 1998.
The NATO force, criticised by some for its lack of results, has noticeably stepped up efforts to tighten the net around Karadzic, who is believed to move frequently between hideouts in eastern Bosnia and his native Montenegro.
He and his former military commander Ratko Mladic, also a fugitive, are wanted on genocide charges for the siege of Sarajevo and the 1995 Srebrenica massacre of up to 8,000 Muslims.
There is a $5 million bounty for the capture of Karadzic.