Sayfullo Saipov, seen in October 2016 after an arrest in St. Charles County, Missouri.
CNN  — 

Deliberations will resume on Monday in the second phase of the death penalty trial of a man convicted of striking and killing eight people with a rented truck in New York in an effort to support the terror group ISIS.

The panel deciding whether Sayfullo Saipov will be sentenced to the death penalty or life in prison had resumed deliberations midday Thursday after a brief pause due to a jurors’ family emergency.

Saipov, an Uzbekistan native living in the US, was convicted of terror-related crimes in Manhattan federal court in January.

US District Judge Vernon Broderick seated an alternate in place of the juror who was excused on Thursday. The judge instructed the jury, with the newly empaneled member, to start their deliberations from the beginning. Three alternates remain.

Broderick denied a defense motion for mistrial, citing legal precedent that allows an alternate to replace an excused juror in similar situations.

Saipov’s defense counsel argued that death penalty statutes require that the same 12 jurors who convicted the defendant also deliberate during the penalty phase.

At about 4:45 p.m. Thursday, the jury said in notes to the court that it wanted to end deliberations for the day. There will be no deliberations on Friday and jurors will return on Monday. Deliberations began on Wednesday.

Closing arguments during this penalty phase of court proceedings wrapped on Tuesday, with one prosecutor for the US Attorney’s Office for the Southern District of New York calling Saipov a “proud terrorist” who plotted to kill as many people as he could in the 2017 attack.

“When ISIS called upon him to fight overseas or attack here, he chose here – this city,” prosecutor Amanda Houle said. “The defendant spent years cultivating the hate that was the foundation for his attack.”

Defense attorney David Patton asked the jury Tuesday to spare Saipov’s life for moral reasons, adding that Saipov’s death “is not necessary to do justice.”

Two Americans and six international tourists were killed in the attack on Halloween in 2017, the deadliest terror attack in New York City since 9/11. At least a dozen other people were injured.

Saipov drove a rented U-Haul truck into cyclists and pedestrians on Manhattan’s West Side bike path, then crashed the vehicle into a school bus, authorities said. After leaving the truck while brandishing a pellet gun and paintball gun, he was shot by a New York Police Department officer and taken into custody, officials said.

Saipov was convicted on multiple charges, including counts of murder in aid of racketeering activity, assault with a dangerous weapon and attempted murder in aid of racketeering activity, provision of material support to ISIS, and violence and destruction of a motor vehicle.

The 12 jurors must come to a unanimous decision in favor of the death penalty for the punishment to be applied, otherwise he will receive a sentence of life in prison.

Closing arguments

Recounting trial testimony from surviving members of the attack as well as family members of the victims, Houle told jurors Tuesday “there can be no justice in this case without a close hard look at the anguish that the defendant chose for these families.”

Saipov has been unrepentant following his arrest, the prosecutor said, recalling prison guards testified at trial that they heard Saipov “yelling about cutting off heads” in his prison cell.

Houle asked the jury to hold Saipov accountable by sentencing him to death.

“He chose to do all of this to support a vile terrorist organization that hates Americans and seeks to kill them,” she said.

“He chose to attack a protected bike path on Halloween afternoon in the heart of the city filled with innocent people and surrounded by children. And he celebrates and stands by those choices without any remorse, which shows you his depravity and the danger he poses. He chose to raise the stakes of justice. That’s on him.”

Defense attorney Patton – who during court proceedings did not offer excuses for Saipov’s behavior – told jurors that Saipov’s life should be spared on moral grounds.

“It is not necessary to kill Sayfullo Saipov. It is not necessary to keep us safe. It is not necessary to do justice,” Patton said.

“By your verdict last month, you guaranteed he will spend the rest of his life in prison and not just any prison, he will be sent to one of the most isolated, solitary, locked away places on the face of the planet,” he told jurors. “But now you face a very different and truly extraordinary decision – whether another human being should live or die. It is a unique, individualized moral decision.”

Patton also noted that Saipov’s family members hoped he would not be sentenced to death, in part because he is a parent to three children. Several family members traveled from Uzbekistan to testify in Saipov’s defense, including emotional testimony from Saipov’s father, who at one point tried to apologize in court for his son’s actions.

Saipov came to the US from Uzbekistan in 2010 and was living in New Jersey before the attack. He became a legal permanent resident, lived with his wife and three children and drove for Uber, according to officials.