Opening arguments in the federal murder trial of Christian Tarantino were postponed Monday morning in Central Islip when four jurors and alternate jurors were dismissed.

One juror was excused because he or she failed to show up at the federal courthouse Monday. Three other members of the panel asked to be dismissed, and District Judge Joanna Seybert granted their requests.

Seybert told the remaining jurors in court that the dismissed jurors were “”unable to continue.”” She did not elaborate on the reasons for their being removed from the jury.

The dismissals left 12 jurors and two alternates to hear the case.

Seybert and attorneys hoped to pick four new alternate jurors before opening arguments, which were set to begin at 2 p.m. Monday. Opening arguments had been scheduled for 10 a.m. Monday, but were postponed because of the juror dismissals.

Prosecutors say Tarantino, of Dix Hills, participated in a 1994 armored car robbery in Muttontown in which a security guard was killed.

Prosecutors say Tarantino later killed two men who participated in the heist because he believed they were acting as federal informants.

Late Monday morning, about two dozen potential alternate jurors were questioned by prosecutors, Tarantino’s attorneys and Seybert.

Jurors are not being identified in court because Seybert ruled that Tarantino is dangerous.