Volen Siderov, leader of Bulgaria's far-right nationalist party Ataka, during his interview for TV7 Tuesday morning. Photo by TV7

Notorious Bulgarian businessman Mihail Mihov has been killed to cover up crimes of former Prime Minister, Boyko Borisov, according to the top nationalist in the country.

Speaking in an interview for TV7 Tuesday morning, Volen Siderov, leader of the far-right nationalist party Ataka, said he had off-the-record information from insiders from Borisov's formerly ruling center-right party, Citizens for European Development of Bulgaria party, GERB, that Mihov had been injected with poison simulating the signs of a heart attack.

He stressed the information was very reliable and should be used as grounds to reopen the probe in the case.

According to Siderov, the murder aiming at covering up Borisov's deeds, has been masterminded and ordered by his Deputy and former Interior Minister, Tsvetan Tsvetanov, and has been carried out by an organized crime group.

After Borisov's resignation, from supporting him and GERB, TV7 turned virulently critical to them.

The head of the Bulgarian Basketball Federation, controversial businessman Mihail Mihov, was found dead in a hotel room on March 30, 2011.

According to official; autopsy results, Mihov has passed away from "fast heart failure over acute coronary deficiency." The autopsy report was sent to the Sofia Prosecutor's Office.

47-year-old Mihail Mikov is the owner of the three Bulgarian breweries, (hence his nickname "Misho Birata" - i.e. "Misho the Beer"). In addition to having been the President of the Bulgarian Basketball Federation since 2008, he was also the Honorary Consul of Brazil in Varna.

Shortly after Mihov's body was found, the Bulgarian Basketball Federation confirmed in a statement that its President had died of a heart attack; meanwhile, Bulgarian media were quick to describe Mihov's death as mysterious.

Mihov's body was found in the RIU Pravets Resort Hotel, in the town of Pravets, northeast of Sofia, which, according to unofficial information is owned by tycoon Valentin Zlatev, the CEO of Lukoil Bulgaria.

In mid-January 2010, Mihov became notoriously known through his involvement in the "Tapegate" scandal. At a press conference in January, the Galeria weekly released a tape of a conversation between Borisov and the head of Bulgaria's Customs Agency Vanyo Tanov, alleging that Borisov provided a cover-up for Mihov.

The tapes reveal that Borisov had called Tanov with an order to immediately pull out all Customs agents from Mihov's factory over an agreement that he made with the businessman, and that the "Ledenika" boss personally complained to the Prime Minister that the Customs inspected his plant in spite of their arrangements. The authenticity of the compromising tape involving Mihov's name was never unconditionally proven.