SOFIA (Reuters) -- Last month, a bomb tore through Vasil Ivanov's apartment, blowing out sturdy brick walls and smashing windows throughout his 12-storey building.

Ivanov, a Bulgarian investigative journalist who has uncovered cases of crime and abuse of power among police, notaries and state officials, had received threats over his stories before, but was shocked by the brutality of the attack.

"I expected something like this to happen. I thought I might be shot at, or beaten up, but I didn't expect them to try to kill so many people," he said.

No one was hurt, but the blast has had deep reverberations across Bulgaria, a poor Balkan state that is struggling to shed its "wild-east" reputation and prove it is ready for European Union membership next year.

The explosion was far from unusual. Car bombs are common.

Even more frequent are shootings, usually by snipers or machinegun-wielding thugs, who since 2001 have killed some 150 people, including Bulgaria's top banker, the owner of a first division soccer team and a leading customs official. But no one has been convicted for any of the crimes, and in most cases police have no leads on who the shooters were. ------Judiciary blamed

Diplomats and analysts lay the blame on the graft-prone Judiciary, saying it has created a "climate of impunity" in which underworld gangs operate without fear of prosecution.

They say crime barons born from former communist secret services control large parts of the economy through networks of legitimate and illegal businesses, helped by corrupt high-level officials.

"There is a society of evil here," said a senior diplomat from an EU state who, like many of his colleagues, would speak about the issue only if he was not named. "These gangs are everywhere and control everything: Private industry, municipalities, members of Parliament. Everything."

The head of the Supreme Civil Court, Ivan Grigorov, denied accusations that the judiciary was to blame.

"The observation that the Bulgarian judges do not work is wrong and insulting. They are in the front-line on solving cases," he said.

The EU's executive Commission has marked graft and crime as the key stumbling blocks to Bulgaria's 2007 accession bid.

It gave Sofia an end-April deadline to show "concrete results" ahead of a May 16 report where it will either recommend Bulgaria be allowed to join next year or be delayed until 2008.

But the date has come and gone, and Western experts are baffled by a lack of progress.

Murders still go unsolved, while last month police found two men in a car full of illegal guns -- sniper rifles fitted with silencers, the favored weapons of underworld hit men -- but did not detain them because of their "poor health".

The Socialist-led government has pushed through new laws including a penal procedure code simplifying investigations and constitutional amendments to boost judiciary accountability.