Lawyers for a man convicted of killing eight people along a Manhattan bike path say prosecutors are seeking “eye for an eye” justice by using tearful testimony from victims and their families to convince a jury to order death.

They asked the judge presiding over the death penalty phase of Sayfullo Saipov’s trial to declare a mistrial over the issue.

“The government’s victim-impact evidence has been laden with emotional testimony, improper references to and characterizations of Mr. Saipov and his crime, and appeals to jurors’ emotions and sympathy for the victims and their plight,” the lawyers wrote.

The request came late last week as the lawyers prepared to begin presenting evidence to support their arguments against the death penalty as early as Tuesday, when the trial resumes and prosecutors complete their presentation. If any juror votes against death, Saipov will serve a life prison sentence.

Late Monday, prosecutors filed a response to the defense’s request for a mistrial, saying it was meritless and that emotional testimony by and about victims “does not approach, much less cross, the bounds of the law.”

They added: “The contested testimony did not offer opinions or characterizations of the crime, did not comment on the appropriate sentence, and did not — by any means — otherwise render the trial fundamentally unfair.”

Saipov, 35, was convicted last month of killing eight people and seriously injuring about 18 others Oct. 31, 2017, when he raced his rented truck onto a bike path in lower Manhattan along the West Side Highway. Arrested at the scene, he said he was supporting the Islamic State group.

The same jurors who heard numerous victims and family members of the dead tearfully testify before convicting Saipov have watched many others describe during the last week how their lives have been permanently altered by the terror attack. Some witnesses have testified twice.

Testimony did not occur Friday, when defense lawyers made their mistrial request, describing emotional testimony a day earlier as “the most forceful and evocative so far.”

They also made the unusual request of asking the judge to order that audio recordings of the court proceedings used solely by court stenographers to ensure transcripts are accurate and be preserved, presumably so an appeals court panel can hear the extent of the emotional testimony.

In their filing, defense lawyers cited some of Thursday’s testimony, including by Belgian witness Alexander Naessens, whose wife, Ann-Laure Decadt, was killed.

He said his children “will never have their mother, never have the most important person in their life, never.”

“And as for me, you know, my life is ruined,” Naessens said.

Defense lawyers wrote that the testimony “transcended a mere description of pain and loss and all but urged jurors to end Mr. Saipov’s life because he had ended Ms. Decadt’s and ‘ruined’ the lives of her husband and children.”

The defense lawyers also complained that prosecutors followed Naessens’ testimony by playing recorded jail phone calls between Saipov and his children in what they described as an obvious attempt to invite jurors “to exact revenge on Mr. Saipov for the sake of Ms. Decadt’s children.”

“This is nothing more than an appeal for an ‘eye for an eye’ justice that encourages the jury to ignore or disregard any mitigation and is otherwise irreconcilable with the jury’s task: To soberly weigh the evidence in aggravation to determine whether Mr. Saipov deserves the ultimate punishment,” they added.

The defense lawyers also said a mistrial might be necessary because of the emotional testimony by Lieve Wyseur, Ann-Laure Decadt’s mother.

“Having wept and sobbed through most of her testimony, in visible fits of anger at times, Ms. Wyseur’s presentation was a quintessential appeal to passion and emotion,” they wrote.

“Of course, the defense is not criticizing the witnesses for the grief and pain they feel over the loss of Ms. Decadt,” they added. “However, it is indisputable that the penalty phase of a federal capital proceeding is not the forum for victims to freely express their emotions or, in Ms. Wyseur’s case, vent their (understandable) rage and torment.”

A spokesperson for the prosecutors declined comment.

During the trial’s penalty-phase, Judge Vernon S. Broderick repeatedly urged witnesses to request a break if they believed they were about to be too emotional, and he has made rulings to disallow some audio or video recordings that he concluded might be unfairly prejudicial.

During the presentation of the defense’s case, members of Saipov’s family were expected in a courtroom that has often been filled with victims and family members of the dead.

New York does not have capital punishment and hasn’t executed anyone since 1963, but Saipov’s trial is in federal court, where a death sentence is still an option. The last time a person was executed for a federal crime in New York was in 1954.