SOFIA, Bulgaria — Hours after radio host Bobbie Tsankov was assassinated in broad daylight in central Sofia, Bulgaria's capital, on Jan. 5, cops arrested reputed mobster Krasimir Marinov for allegedly masterminding the shooting. On the same day, they also announced a dragnet to find Marinov's younger brother and alleged co-conspirator, Nikolay.

But two weeks later, Marinov, nicknamed "The Big Margin," was released on bail because the judge said prosecutors lacked evidence to detain him. His brother, known as "The Little Margin," remained at large. On Jan. 21, the elder Marinov was again arrested, this time on drug-related charges. Since then, he's stayed in jail. His brother is still on the lam.

It's not the first time the Margin brothers have treated the Bulgarian judicial system like a drive-through. They have been in and out of court of since 2006 on allegations of plotting other midday street shootings. Because they claim to suffer from ill health, their trial has been postponed several times while they have been under house arrest, where they have continued to oversee their alleged criminal empire.

Sofia City Prosecutor Nikolay Kokinov shrugs when asked why he can't make charges against the brothers stick. "I'm not able to say where the mistake was," he said. "It is hard to prosecute such a case when there is a person who ordered the murder, and you don't have the person who perpetrated the crime."

Crime and corruption have again become a crisis in Bulgaria since Tsankov's death. On Jan. 19, the country's foreign minister, Rumiana Jeleva, resigned after withdrawing her candidacy for a seat on the European Commission amid accusations she lied on her financial disclosure forms. The scandal suggested that high-level political corruption was resurgent while hitmen were gunning down well-known figures in the streets.

Last year, the U.S. Embassy in Sofia released a list of about 140 contract murders in Bulgaria between 1993 and 2008. Authorities arrested numerous suspects connected to those public shootings, but no high-level bosses have been convicted.

The incidents rekindle memories of the unsolved shootings that led the European Union to suspend 500 million euros in aid to Bulgaria in 2008 because of officials' failure to end the country's ongoing crime spree. The move humiliated Bulgaria, the EU's poorest member, and was a key factor in Prime Minister Boyko Borisov's win last year over the then-Socialist government.

Ready to live up to his image as a tough guy, Borisov recently dressed down the country's top law enforcement officials at a press conference, calling for significant convictions by next year. His ministers vowed to end the complacency on crime that has bedeviled past governments.

"Some 250 to 300 emblematic figures of Bulgaria's underworld have been tormenting the country for the last 20 years," said Interior Minister Tsvetan Tsvetanov at the event.  "We are facing difficulties because of all the time that has been lost."

Further delays could also be pricey. Much of the previously frozen EU money has since been released, but European Commission spokesman Dennis Abbott said Brussels is considering suspending as much as 1 billion euros in EU funding for water treatment and other projects because Sofia won't produce audits, raising suspicions about the fate of previously transferred cash.

"Not enough of this money is reaching the actual beneficiaries on the ground," said Abbott.

Experts also said the global recession — which arrived late to Bulgaria — could exacerbate relations between mafia clans and lead to more violence, making Borisov's job still harder. Criminologist Tihomir Bezlov at the Center for the Study of Democracy, a Sofia think tank, said recent internecine fights over shrinking spoils have resembled those among criminals after the fall of communism.

"We see more rude relations, more brutality," said Bezlov. "Maybe we'll have some return of the middle 1990s."

Borisov also must depend on judges in order to fulfill his pledges, but it's not clear he can count on them. Younger Bulgarian magistrates and United States federal justices who have participated in U.S.-funded training missions have said many senior Bulgarian judges are unreconstructed communists with little interest in the law beyond enriching themselves.

Over the past year, those claims have been underscored by a scandal involving influence peddling that has rocked the Bulgarian judiciary. Prosecutors have accused 27-year-old disco owner Krasio Georgiev of offering to help judges secure promotions for hundreds of thousands of euros.

It's not known if Georgiev wielded such influence or was a scam artist, said Bezlov, but phone records show he had thousands of conversations with jurists throughout the country. Never before have judges been so implicated in corruption. "The Krasio case is very important," Bezlov said. "It broke the ice."

Sofia City Prosecutor Kokinov also expressed optimism. The government is giving him more support than ever, he said. Proposed reforms stemming from the Georgiev case might erect better firewalls between judges and profiteers, he added.

And while the Margin brothers have escaped convictions, Kokinov said their recent legal hassles have disrupted their operations. That means new, less experienced bosses are assuming more responsibilities, giving him more opportunities to catch them.

"They'll make more mistakes now," said Kokinov. "They're becoming new, and when a person is new, they make more mistakes."