A sniper shot and killed the owner of Bulgarian premier league soccer club Lokomotiv Plovdiv on Thursday after they beat OFK Belgrade 1-0 in the UEFA Cup second qualification round.
It was the latest in a string of shootings, bombings and other violence blamed on Bulgaria's criminal underworld that is believed to have been behind the killings of scores of people in recent years. The violence has scarred the country's image as it vies for EU entry in 2007.
Police said Georgi Iliev's name had cropped up in drug investigations and he had a history of criminal charges, including a rape conviction in 1986. His brother, also a suspected mob boss, was murdered in 1995.
"We had several operations on drug trafficking, especially of cocaine and links to Spain, and we have operational data which leads to him," Interior Ministry Chief Secretary Boiko Borisov told a news conference on Friday.
Officials said the 39-year-old, who ran hotels and night clubs, was killed while talking on his mobile phone at one of his bars at the Sunny Beach Black Sea resort.
"The shot was precise and hit him in a vital area from a long distance. It showed it was the act of a professional," Bourgas city Police Chief Krasimir Petrov told news agency BTA.
Dozens of witnesses saw the murder, which happened just 40 minutes after Lokomotiv Plovdiv won the match. Media said the team's players were to have joined him in the restaurant to celebrate.
Western officials say organised crime groups control large parts of the economy with a murky mix of legitimate and illegal businesses and combined with a weak rule of law are a serious stumbling block to Bulgaria's efforts to join the EU.
Authorities have never convicted a single suspect for dozens of bloody gangland hits. Diplomats blame the failure on a slow and graft-prone judiciary that Brussels has warned must be fixed or it will delay membership by a year until 2008.
Iliev's death prompted a swift reaction from the new Socialist-led government, sworn in last week after winning June elections on an anti-crime, rule of law platform.
Interior Minister Rumen Petkov said authorities would investigate the tax, property, income and customs dealings of suspects and step up surveillance and raids on known gangs.
"We are adamantly committed to have a zero-tolerance policy towards organised crime. We express our unwavering will to fight it with all legal means," he said.