CHICAGO  —  Eleven reputed Chicago mob figures were indicted Monday on charges of plotting at least 18 murders, including the 1986 hit on the crime organization's top man in Las Vegas, Tony "The Ant" Spilotro (search), who was buried in a cornfield.

Prosecutors described the racketeering indictment as one of the most far-reaching in the history of Chicago. They would not comment on how or where they got the evidence that led to the charges.

Those indicted included 63-year-old James Marcello (search), identified by FBI officials as the leader of organized crime in Chicago, and longtime mob leader Joey "The Clown" Lombardo (search), 75. Marcello was arrested, and a manhunt for Lombardo was under way in Chicago.

Fourteen alleged mob figures were indicted in all, including 11 in a murder conspiracy dating back to 1970 and three on gambling and other charges. Prosecutors said seven actually murdered someone or agreed to commit murder.

"The mob takes a hit today," U.S. Attorney Patrick J. Fitzgerald told reporters in announcing the indictment — the result of an investigation that was code-named Operation Family Secrets.

Spilotro, a Chicago mob enforcer, ruled Las Vegas in the 1970s and early 1980s, and Joe Pesci played a character based on him in the 1995 Martin Scorsese movie "Casino."

The badly beaten bodies of Spilotro, 48, and his brother Michael, 41, were found buried in an Indiana cornfield in 1986. It has been reported for years that the Spilotro brothers were buried alive in the field, but Fitzgerald said Monday they were killed elsewhere before being dumped.

Prosecutors said all of those charged were connected in some way to the Chicago mob, also known as the Chicago Outfit or the Chicago Syndicate. Among those charged were two retired police officers accused of informing one of the suspects about possible mob members who were helping federal investigators.

"This is the first investigation that I can recall and indictment I can recall that involves so many murders, which really go to the heart of what the LCN (La Cosa Nostra) is, a bunch of murderous thugs," said Robert D. Grant, agent in charge of the FBI's Chicago office.

Agents in three states — Illinois, Arizona and Florida — began rounding up the defendants early Monday. Two of them, Lombardo and alleged mob enforcer Frank Schweihs, 75, were still missing and classified as fugitives.

Lombardo's attorney, Rick Halperin, denied his client was involved in any of the activities and said he was not a fugitive.

"He looks more like a throw-in than anything else," Halperin said.

Lombardo was previously convicted in federal court in Chicago in a major mob investigation of corruption involving the Teamsters Central States Pension Fund.

Another defendant, Frank Saladino, 59, was found dead Monday morning in a hotel room in Illinois when FBI agents went to arrest him. They said he appeared to have died of natural causes, although the official cause of death had not yet been determined.

Saladino had $25,000 in cash and $70,000 in checks with him in the hotel room, according to FBI agents.

The attorney for James Marcello — Marc W. Martin — did not immediately return calls for comment.