More than 100 FBI (search) agents and police officers arrested dozens of suspected mobsters Tuesday in an early morning raid that prosecutors called a decisive blow against a weakened Bonanno crime family (search).

Law-enforcement officials unsealed a 20-count indictment that charged 27 members and associates of the Mafia (search) family with murder, conspiracy and other crimes.

Police said those indicted were responsible for seven previously unsolved homicides in recent decades.

"Today's indictment caps a yearlong series of indictments that represent the broadest and deepest prosecution ever of a New York City-based organized crime family," said U.S. Attorney Roslynn Mauskopf.

The indictments stem from a four-year investigation that for the first time in memory saw a high-ranking member of a New York City crime family wear a wire to high-level family meetings, prosecutors said.

Law-enforcement officials said successive prosecutors had put the family in such disarray that its code of silence was coming apart.

"The code of omerta has been abandoned," said Pasquale D'Amuro, assistant director of the FBI's New York office.

In another sign of a breakdown of Mafia discipline, the investigation captured suspects discussing the assassination of family members of cooperating witnesses.

"If you take one kid, I hate to say it, and do what you gotta do, they'll ... think twice," acting Bonanno boss Anthony Urso is alleged to have said during a family meeting last year.

Urso's attorney, Edward Janks, said the case was based on an "avalanche of lies" from government informants.

Meanwhile, other suspects entered not guilty pleas at their arraignments.