BELGRADE (AP)--A U.K. citizen of Croatian Serb origin, has been arrested in Serbia on suspicion that he took part in the execution of Croat prisoners of war during the 1991 Serb-Croat war. 

Milorad Pejic was arrested at the airport in the Serbian capital, Belgrade, on March 19, said a statement by Serbia's war crimes prosecutor's office obtained by The Associated Press Tuesday. 

Pejic is among a group of suspects, mostly former paramilitary fighters, accused of gunning down about 200 Croats at a pig farm in eastern Croatia after the fall of Vukovar in November 1991. 

The execution is considered to be one of the most brutal crimes of the wars that began after the breakup of the former Yugoslavia in the 1990s. 

In 2005, Serbia's war crimes court convicted 14 former Serb soldiers for the execution-style killings at Ovcara and sentenced them to up to 20 years in prison. 

But Serbia's Supreme Court has ordered a retrial, citing alleged irregularities in the initial proceedings. This has triggered outrage among the victims' families. 

It wasn't immediately clear whether Pejic will join the other suspects at the retrial or needs to be formally charged first.