The shooting happened just hours after the head of an energy company that repairs Bulgaria's only nuclear power plant and other big energy utilities was shot dead in Sofia.
The Socialist-led government is under growing pressure from the European Union and at home to stop procrastinating and get serious about fighting rampant crime and graft.
There have been more than 150 gangland assassinations since 2001. But despite its campaign against crime and graft, Bulgaria has failed to convict a single suspect, nor has it charged any senior officials with graft.
Bulgarian Georgi Stoev, 35, the author of a series of books on the emergence of Bulgaria's underworld after communism collapsed in 1989, was shot once in the head in front of a hotel in central Sofia, police said.
Doctors said he was in a critical condition.
On Sunday, police found Borislav Georgiev, the manager of Atomenergoremont, shot twice in the head in the entrance of his apartment block. The energy company is majority owned by a businessman, who local media say has links to crime groups.
Diplomats say the killings from the past few years are the work of powerful crime gangs who, born in part from the former Soviet secret services, control large parts of the economy with help from slow and graft-prone courts and high-level corruption.
The EU, which Bulgaria joined last year, has warned Sofia it might lose millions in EU aid if it does not show tangible results in taming organised crime and rampant graft.
On Friday, the rightist opposition asked parliament to hold a vote of no-confidence against the coalition government, accusing it of having intertwined with organised crime.
The government is struggling to clean its image after high-ranking police officials were arrested last month and accused by prosecutors of passing sensitive information to shadowy businessmen, and irregular phone tapping.
Last Mod: 08 Nisan 2008, 08:49