The developments followed the earlier removal of a juror, who was replaced by an alternate. Yesterday's removal of a second juror and the remaining alternate left 11 jurors, instead of 12, resulting in a mistrial.
Nicodemo, 42, will remain in jail without bail.
He was on trial for the Dec. 12, 2012, slaying of Gino DiPietro, another reputed mobster with a history of federal drug convictions.
DiPietro, 50, was gunned down in front of his house on Iseminger Street near Johnston in South Philadelphia, just before 3 p.m.
Zarallo told the jury last week that Nicodemo was the getaway driver whose job was to dispose of the .357-caliber Magnum murder weapon.
Although the gunman has not been arrested, the prosecutor suggested he might have been Domenic Grande, a friend of Nicodemo.
"Gino DiPietro was targeted. This was not a robbery. Nobody rifled through his pockets," said Zarallo, who described Nicodemo and the gunman as broad-day assassins.
Other than saying "the motive was murder," Zarallo gave no reason that DiPietro was targeted.
Surveillance-video evidence shown to the jury appeared to capture images of Nicodemo's black Honda Pilot SUV near the crime scene.
Prosecution witness Louis Houck testified that he saw the masked gunman run from his fallen victim and get into the passenger side of the waiting SUV. He said he memorized the license-plate number and gave it to police.
Within an hour of the slaying, police were at Nicodemo's home on 17th Street near Hartranft, South Philadelphia, where they arrested him and recovered the weapon from inside his SUV.
Defense lawyer McMonagle, however, told the jury that Zarallo's case was in "chaos" given that Grande has never been arrested in the slaying.
McMonagle contended that as Nicodemo was driving along, the masked gunman ran from an alley and jumped into his SUV, placed the gun under the seat then bolted on foot.
A shaken and sweat-drenched Nicodemo then drove home only to be arrested for a crime he had nothing to do with, McMonagle said.
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