A Bosnian tycoon and head of a party in the ruling coalition was arrested on Monday on suspicion of obstructing justice, just weeks before the Balkan
country is expected formally to apply for European Union membership.
Fahrudin Radoncic is a former owner of Bosnia's largest newspaper, Dnevni Avaz, and leader of the co-ruling Union for Better Future (SBB) party.
His arrest follows that of two other SBB officials this month on suspicion of intimidating a witness in the high-profile trial in Kosovo of accused Balkan drug lord Naser Kelmendi.
Party officials said the arrest, in connection with the same trial, was carried out by individuals from a "judicial mafia."
It was unclear what ramifications his arrest might have for the ruling coalition, which is just weeks away from applying for Bosnian membership of the European Union, two decades after the end of a 1992-95 war.
The fall-out might be limited if he is freed from police detention after 24 hours of questioning, before any trial some time in the future.
The prosecution could ask for one month's detention, as was the case with other two officials arrested.
Kelmendi was arrested in Kosovo in 2013 on a Bosnian warrant over his alleged involvement in organized crime and the 2007 killing of former Bosnian warlord Ramiz Delalic but was not handed over to Bosnia because of the lack of an extradition accord between the two countries.
He is on trial in Kosovo on charges of trafficking drugs, organized crime and the murder of Delalic.
Police said they raided several other locations for evidence, including the building where the Dnevni Avaz offices are located.
The newspaper's editors condemned the raid by armed police as "a brutal pressure on media freedom and an attempt of intimidation".
The State Investigation and Protection Agency said the target of the raid was not the newspaper but offices used by Radoncic in the same building.
Several high-ranking Bosnian government officials have been tried for organized crime and corruption but there have been no convictions so far.