A day after Roumen Petkov announced his resignation as interior minister he said he would file libel claims against German journalist Juergen Roth, Volen Siderov, leader of ultra-nationalist Ataka party, and  Mihail Mihailov, a municipal councilor from Petkov's home town of Pleven.

On April 14 2008 Petkov told reporters he would sue Roth in relation to his book on organised crime in Bulgaria which presented  Petkov in a negative light. Roth quoted anonymous Interior Ministry's top officials who said that Petkov had personally controlled drug trafficking from Bulgaria to Turkey and the Middle East.

Roth's book is still to be published but extracts from it were published by mediapool.bg. According to Roth he had simply quoted sources from the ministry. “I haven't slandered Petkov” Roth told Deutsche Welle on April 10 2008.

Petkov will sue Siderov for his statements that Petkov was the mastermind behind an incident that happened on Trakiya Highway in 2006 when Siderov's car collided with another vehicle and Siderov allegedly waved a gun at the driver. Later Siderov said that this was an attempt on his life inspired by Petkov. Currently there is a court case pending against Siderov in relation to the incident where he is accused in giving false testimony.

The third libel claim Petkov said he would file was against Mihail Mihailov and refers to Mihailov's claims that Petkov was a key figure in the financial crises that shook Bulgaria in the mid 1990s. Petkov had acted under the direct supervision of Andrey Loukanov, former prime minister who was shot dead in 1997 in front of his home in Sofia Mihailov said in a number of media appearances. Both Petkov and Mihailov are members of Bulgarian Socialist Party.