Three doctors will perform the autopsy of the Bulgarian controversial businessman Mihail Mihov, who was found dead in a Pravets hotel room on March 30.

"I firmly stand behind my words – the causes of Mihov's death were not violent, but the exact reason will become clear after the autopsy today," said the director of the Sofia Regional Directorate of the Interior Ministry, Chief Commissioner Nikolay Nikolov, in a TV interview on Thursday.

The body of the 47-year-old president of the Bulgarian Basketball Federation and Ledenika brewery boss 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.

The initial information said that Mihov died from a heart attack. However, later officials from the Interior Ministry announced that the pre-trial proceedings were brought under Article 115 of the Penal Code – for murder.

On Thursday, Nikolov explained that the pre-trial proceedings are for murder since this is a legislative procedure.

"The autopsy is today. We can no longer speculate. The real cause of the death will be announced, whether it is heart attack, stroke, etc," Nikolov said.

He declined to give more details before Mihov's autopsy. However, he said that the investigation is working on all versions, including murder.

Mihail Mihov, aka Misho Birata (Misho the Beer) made headlines following a scandalous leaked wiretap, released in the middle of January by the Galeria weekly.

The conversation featured was between Customs Agency head Vanyo Tanov and Finance Minister Simeon Djankov. It tackled issues, related to the activities and license of the Ledenika brewery and its owner.

The recordings, whose authenticity was never unconditionally proven, allege that PM Boyko Borisov provided a cover-up for the owner of the "Ledenika" beer company, Mihail Mihov. They made clear that President Georgi Parvanov made a promise to Mihov, which he did not keep.

The tapes reveal that Borisov had called Tanov with an order to immediately pull the tax agents out of the factory and that the "Ledenika" boss personally complained to the country's prime minister.