Officers from Bosnia’s Serb-led entity Republika Srpska assisted by local Sarajevo police raided the Klix newsroom in the capital on Monday in an attempt to discover the origins of the allegedly incriminating audio recording.

Local media reported that police were copying material from the newsroom’s computers.

The raid follows last week’s questioning of Klix’s editors and journalists about the recording that the website posted online in mid-November, after the Bosnian general elections.

The police wanted to know how and from whom the website got the material.

In the audio recording, a woman can be heard talking about two lawmakers who her party had “bought” in order to ensure that it had a majority in the Republika Srpska entity parliament.

Klix has admitted that it cannot verify the authenticity of the recording or prove that the woman’s voice was that of Bosnian Serb Prime Minister Zeljka Cvijanovic.

No information was provided about which parties the two MPs come from either.

The voice on the recording says that Republika Srpska’s ruling Alliance of Independent Social Democrats, SNSD, had paid the two deputies to support it in the entity parliament.

The SNSD has dismissed a recording as a forgery.

Borka Rudic, secretary general of the Bosnian Journalists Association, said that the raid on Klix was a “brutal attack” on media freedom.

“I guess that the raid was launched because of the published audio recording. They have not given us any information, nor are they letting us in into the Klix newsroom,” Rudic said.

She said that the move was “unacceptable” and that journalists have the right to protect their sources.

“It is absurd that police are investigating how the media got the recording and from who, instead of investigating its authenticity and whether someone bought MPs,” she told Fena news agency.