Assistant District Attorney Brian Zarallo and defense attorney Brian J. McMonagle said they could not comment on the reason the jurors were disqualified - whether they had been approached by someone outside court or had violated the judge's instructions by reading news coverage of the trial.
"There are questions that still need to be answered, but I can't comment further," Minehart responded to a reporter's questions through a courtroom aide.
One person familiar with the inquiry said that at least one juror would be questioned by detectives to determine what happened.
Despite Nicodemo's alleged ties to organized crime, mentions of the mob, Mafia, or La Cosa Nostra have been absent during the trial. Minehart had barred lawyers from bringing up a mob aspect in the case unless they could show that the Dec. 12, 2012, killing of Gino DiPietro, 50, was linked to organized-crime activities.
Although DiPietro served prison time for drug and gun violations, his family has said he was not a mobster, and authorities have never alleged that he was a formally initiated member of the South Philadelphia mob.
Rumors of a possible mob connection were rife when DiPietro was killed, if only because the shooting happened during the first federal racketeering trial of alleged organized crime boss Joseph "Uncle Joe" Ligambi.
The federal jury could not reach a verdict in the case against Ligambi, forcing a retrial that ended in January with a second hung jury. Federal prosecutors have since decided not to bring the 74-year-old Ligambi back for a third time, and he is a free man.
In the Nicodemo case, Minehart on Tuesday set a status hearing for June 12, but told relatives of Nicodemo and DiPietro that there was no date for a retrial.
Testimony began May 13 before a jury of seven women and five men, with two alternates - one female and one male. By the second day, the female alternate replaced Juror No. 3, a woman who reportedly read news accounts of the case.
The trial proceeded through Monday, when the prosecution's case ended.
But when the trial resumed Tuesday morning, it was instantly clear there was a serious problem: Two jurors were missing, and security was heavy - nine deputies flanked both side walls of the courtroom.
After the jurors left, everyone remained in place for 30 minutes.
Nicodemo, 42, remained at the defense table with McMonagle and cocounsel Frank C. DePasquale Jr., while Zarallo sat by himself at the prosecution table, and about 75 spectators sat in the gallery.
DiPietro was gunned down shortly before 3 p.m. as he stood by his pickup truck in the 2800 block of South Iseminger Street in South Philadelphia.
A letter carrier described a man in black, wearing mask and gloves, firing into DiPietro's prone body.
A second witness, a pedestrian, testified that he was walking along Camac Street when he saw a masked man in black run by and jump into a black 2011 Honda Pilot SUV. The witness said he memorized the license plate number, HTK-1942, and told police at the scene.
Within minutes, police identified the car as Nicodemo's and were outside his house in the 3200 block of South 17th Street.
Nicodemo was taken into custody, and a search of his SUV turned up the .357 Magnum revolver used in the killing. It had been wrapped in clothing and stashed behind the driver's seat.
In his May 13 opening, McMonagle said Nicodemo was driving home when he became the victim of an aborted carjacking. He said a masked gunman jumped into the SUV, apparently stashed the gun behind the driver's seat, and then jumped out and fled on foot.