Nikolay Kokinov, chief prosecutor in Sofia, said that if sufficient evidence were gathered, the prosecution would demand that Ataka be banned. According to the Bulgarian constitution, political parties cannot be formed on the basis of ethnic, racial and religious principle, and organisations that preach ethnical and religious hatred are forbidden.
Kokinov said he had asked a subordinate to gather information on a series of incidents involving Ataka leader Volen Siderov and Ataka members.
On 20 May, an authorised peaceful protest by Ataka before Sofia's biggest mosque degenerated into violent clashes in which several people were wounded, including policemen and an Ataka MP.
Reportedly, Ataka supporters spat on prayer rugs laid down outside the mosque and set some on them on fire. Clashes followed, with Ataka supporters throwing stones at the mosque and its loudspeakers.
Following the unrest, Siderov said that Muslims in Bulgaria were preaching jihad, a holy war against non-Muslims, and wanted to install an Islamist state in Bulgaria.
The incident apparently embarrassed Bulgarian Prime Minister Boyko Borissov, who reacted from Poland, where he was on an official visit, by saying he did not know about the incident but always stood for ethnic tolerance.
However, prior to that he had said he would always be grateful to Ataka for the support the political party had given his minority government (see 'Background').
Later on, Borissov placed the blame on both Ataka and the Movement for Rights and Freedoms (MRF), a party harbouring the country's Turkish minority.
"Regrettably, both MRF and Ataka took a direction in the election campaign which is far from pleasant," he said.
Borissov did not elaborate what kind of reproaches he was envisaging vis-à-vis MRF. Many of Borissov's supporters believe that the MRF is a corrupt party which managed to siphon much of the country's resources under the previous government, in which it was a coalition partner.
Live wrestling at talk show
But Siderov, who is a candidate for president and is apparently worried about his low ratings, experienced another hiccup on Sunday after starting a fight during a live talk show on Bulgarian radio.
Reportedly, Siderov hit an MP from MRF, Korman Ismailov. Ismailov hit him back and programme was stopped while the two men wrestled.
According to his own words, Siderov displayed during the show a photo depicting a man with a knife, claiming that he was one of the worshippers at the mosque. He accused "the Islamists" of having started the clash.
"It will be too late when one of them has blown up Sofia's subway. This has already happened in Madrid and in London," he was quoted as saying.
Velichko Konakchiev, the talk show's anchor, said he had never seen anything like the fight between the two men in 21 years of experience on the popular programme.
A Facebook group organised citizens' action to apologise to Muslim worshippers at the Sofia mosque. National TV showed hundreds of flowers laid down in front of the temple, with words of apology for the extremists' behaviour left there by ordinary citizens.
Unlike other countries in the region, Bulgaria experienced no serious ethnic tensions during its transition to democracy and a market economy. Bulgarians are generally tolerant of ethnic minorities and have peacefully coexisted with Turks, Armenians, Jews and Greeks for many years.