Fifty-year-old Dusan Culibrk, who was a member of Bosnian Serb police unit, was arrested in northwestern town Krupa Na Uni, the same region where the crimes were committed almost 30 years ago, prosecutors said in a statement.

A quarter of a century after the Bosnia's war, the local justice system is still working on some 600 war crimes cases, with staggering 4,500 suspects, according to official data.

The 1992-95 conflict left some 100,000 dead in violence that fractured Bosnia's three main communities of Serbs, Croats and Muslims, known as Bosniaks.

Culibrk is suspected of "having participated" in the "execution of 44 Bosniak and Croat civilians", prosecutors said.

The group was taken from the Omarska camp by members of his unit under the pretences of a prisoner exchange, but were instead shot near the village of Donji Dubovik, according to the statement.

Their remains were found in a natural pit in 2000, along with seven Muslim civilians who Culibrk is suspected of shooting to death as they attempted to flee the area.

More then 6,000 people, mostly Bosniaks and Croats, were confined for several months in 1992 in a 'triangle of horror', referring to the Omarska, Keraterm and Trnopolje detention camps.

A shocking photo from one of those camps, showing an emaciated detainee with protruding ribs standing behind barbed wire, brought the world's attention to the ethnic cleansing campaign carried out by Bosnian Serb forces at the time.

According to victims associations, nearly 3,500 people were killed the surrounding region of Prijedor, with several hundred still missing.