ROME (AP)  Anti-mafia prosecutors claimed a major victory over the powerful and growing 'ndrangheta crime syndicate, infiltrating intimate weddings, baptisms and other events to gather information that led to the arrests Tuesday of 305 people, including top bosses, and the seizure of more than $76 million in cash and property. One of the most significant revelations to emerge from the investigation was that the Calabrian mob had a tight hierarchal structure like that of the Sicilian Mafia, and wasn't just an association of clans as previously believed. While expanding its economic reach into the wealthy Lombard region in northern Italy, the 'ndrangheta (en-DRAN-geh-tah) is also concentrating its power in its native Calabria, exerting tight control over all strategic decision-making, anti-mafia prosecutors said. The operation began before dawn with the 4 a.m. arrest of Domenico Oppedisano, the crime group's top boss, in the small coastal town of Rosarno in Calabria. But the investigation owed its success to investigators' ability to infiltrate events like the 2009 wedding of the children of two crime bosses in Calabria, attended by thousands of well-wishers, where Oppedisano was named to his post, said Calabrian anti-mafia prosecutor Giuseppe Pignatone. When Oppedisano was formally elevated some two weeks later, on Sept. 2, the feast of Madonna Polsi, undercover agents got video of the crime syndicate's major bosses all being confirmed in their new positions in the structure, he said. "Police and carabinieri have been able to record since Aug. 1, 2009 all of the major negotiations of the various families," Pignatone told a news conference. That includes some 40 similar meetings in Lombardy, which has become the Calabrian mob's moneymaking center, with operations focusing on excavations for construction sites, trash disposal and real estate. While officials seized euro60 million in cash and property, prosecutors are unable to estimate how much the 'ndrangheta is cashing in each year. Wiretaps indicate that as many as 500 'ndrangheta mobsters are operating in Lombardy, where 160 were arrested. They include Pino Neri, whom police said was in charge of the gang's businesses in Milan, where the 'ndrangheta has been making major inroads. The investigation revealed the 'ndrangheta was extremely "hierarchical, united and pyramidal," and not just clan-based as previously believed, said Italy's chief anti-mafia prosecutor Piero Grasso. That became clear when the Lombard branch, empowered by its riches, attempted to exert autonomy and was cut short when the Calabrian bosses sent a professional killer to murder the would-be upstarts, Pignatone said. The 'ndrangheta has emerged as one of the most powerful of the crime syndicates, even if only since February has Italian law recognized it as a criminal organization. From Calabria, it has spread its tentacles to northern Italy, where it migrated in the 1970s and 1980s, to Germany, and as far away as Canada and Australia. Investigators described the operation as one of the biggest blows ever to an organization that is now considered to be more powerful than the Sicilian Mafia. The raids involved 3,000 police across the country and the charges against those arrested ranged from murder and extortion to arms and drug trafficking and criminal association. The last big operation against the Calabrian mob dates to the 1990s. Since then, the 'ndrangheta has expanded its power, mainly through its grip on drug trafficking. But what Grasso said was particularly worrisome was the crime group's infiltration into the economic arena, a form of mafia entrepreneurship, with the ability to get an inside track when contracts are handed out. Among those arrested was the head of the state health system in the city of Pavia, south of Milan. Prosecutors emphasized that wiretaps were a key to the 'ndrangheta investigation, but declined to speculate on how a proposed new bill that would limit the use of electronic eavesdropping might have affected their work. Premier Silvio Berlusconi, who has been stung by some embarrassing disclosure in published transcripts of private conversations mostly unrelated to investigations, is pushing the measures through parliament. While terrorism and mafia investigations are exempt from the proposed restrictions, magistrates complain that big probes often stem from low-level criminal cases. Passage of the law, they say, will give criminals operating in Italy protection. The restrictions include a strict time limit on wiretaps, which prosecutors say is insufficient, and a level of proof needed to obtain permission to launch the wiretaps that investigators charge is tantamount to evidence needed for a conviction. "Today we violated the privacy of many 'ndranghetisti," Grasso quipped. 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