Chicago ? A federal jury found five aging men guilty Monday in a racketeering conspiracy that involved decades of extortion, loan sharking and murder aimed at rubbing out anyone who dared stand in the way of the ruthless Chicago mob.

The verdicts capped an extraordinary 10-week trial that laid bare some of the inner workings of The Outfit.

The prosecution’s star witness was an admitted hit man who took the stand against his own brother to spell out the allegations, crime by crime. The jury heard about 18 unsolved killings, including the beating death and cornfield burial of Tony “The Ant” Spilotro, the mob’s man in Las Vegas and the inspiration for Joe Pesci’s character in the 1995 movie “Casino.”

The jury deliberated for less than 20 hours. The five men were found guilty of all counts, including racketeering conspiracy, bribery, illegal gambling and tax fraud.

Alleged mob boss James Marcello, 65; alleged mob capo Joseph “Joey the Clown” Lombardo, 78; convicted loan shark Frank Calabrese Sr., 70; and convicted jewel thief Paul Schiro, 70, could now face up to life in prison. The fifth man, retired Chicago police officer Anthony Doyle, 62, was the only one among the five not accused of taking part in at least one killing.