The woman, now decades removed from the crime, said she could nonetheless judge the mob case fairly.
The racketeering case mostly involves illegal gambling and loansharking in Pennsylvania and New Jersey, and there's little violence alleged, other than threats picked up on FBI wiretaps.
The investigation stretches back to about 1999, when former boss Joey Merlino went to prison. Prosecutors say the lead defendant, Joseph "Uncle Joe" Ligambi, has led Philadelphia's La Cosa Nostra since then.
The 73-year-old Ligambi and several co-defendants have pleaded not guilty and plan to fight the charges during the two- to three-month trial. About a half-dozen others have pleaded guilty to taking sports bets, collecting debts and operating illegal video poker machines, but they don't have to testify against their associates at trial.
Ligambi is also accused of defrauding the Teamsters by getting health benefits through a no-show job at a waste disposal company. He remains in custody, along with his co-defendants.
The jurors won't be sequestered, but extra security measures are being taken given the mob's violent history in Philadelphia under earlier crime bosses. Jurors will remain anonymous and be brought to court each day from a remote location.
Ligambi chatted with family and friends in court Monday and laughed with co-defendants as lawyers continued the laborious jury selection process. Opening statements could come by week's end.
U.S. District Judge Eduardo Robreno is presiding over the case.
One potential juror told him that she thought anyone who declined to testify at trial was guilty. She also declared an ingrained bias against the mob.
"I don't think there's any lawful people in the Mafia. I think ... that they're corrupt," the white-haired woman said.
She was dismissed.