A lone juror threw the trial of NYPD Offier Jonathan Diller’s accused killer into disarray Wednesday — declaring he didn’t agree with the verdict after the foreman read what was supposed to be their unanimous decision to acquit on murder but convict on aggravated manslaughter.

The eight men and four women deciding 35-year-old ex-convict Guy Rivera’s fate ended their first day of deliberations with an announcement they’d reached a verdict after just four hours.

But when it came time to poll the individual jurors and Juror No. 5 was asked, “Is this your verdict?” he said, “No.”

The word hit like a vinyl record scratch during an already emotional scene, as Diller’s wife, Stephanie, quietly cried as a supporter held her.

Shocker in trial of NYPD Officer Jonathan Diller’s alleged killer as lone juror balks on verdict
Stephanie Diller, the widow of NYPD Officer Jonathan Diller, is pictured during the trial of Guy Rivera, who is charged with the murder of Officer Diller, at Queens Criminal Court on April 1, 2026. (Gregory P. Mango / Pool)

Judge Michael Aloise told the jurors their decision had to be unanimous, and sent them back in for deliberations.

A few minutes later, the jurors asked through a note how long they’d have to deliberate if they couldn’t reach a verdict, and another juror asked to make a phone call to cancel a real estate appointment.

Before Juror No. 5 dropped his bombshell, the foreman read a verdict of not guilty for first-degree murder, then guilty for first-degree aggravated manslaughter, attempted murder and two counts of criminal possession of a weapon.

Earlier in the day, jurors asked to see a video compilation showing the deadly March 25, 2024 shooting, and asked for a readback of the elements needed to convict Rivera on the top charges against him.

Family and supporters of NYPD Detective Jonathan Diller gather outside the courtroom before prosecution closing arguments in the trial of his accused killer, Guy Rivera, at Queens Criminal Court in Queens, New York City on Tuesday, March 31, 2026. (Gardiner Anderson / New York Daily News)
Family and supporters of NYPD Detective Jonathan Diller gather outside the courtroom before prosecution closing arguments in the trial of his accused killer, Guy Rivera, at Queens Criminal Court in Queens, New York City on Tuesday, March 31, 2026. (Gardiner Anderson / New York Daily News)

Prosecutors say Rivera deliberately shot the 31-year-old officer in the stomach on Mott Ave. in Far Rockaway, in a violent attempt to blast his way out of a car stop that would have otherwise ended with his arrest on gun charges.

Rivera’s defense team argued that he didn’t intend to shoot Diller, and that a gun in his pocket discharged after another officer, Sgt. Sasha Rosen, reached into the parked Kia where Rivera was sitting and grabbed the firearm during a struggle.

Rivera is also accused of aiming the gun at Rosen’s chest, point blank, and trying to murder him, as well, foiled when his .380-caliber handgun jammed.

Rivera was charged with first-degree murder and first-degree aggravated manslaughter in relation to Diller’s death, and Aloise explained to the jurors Wednesday morning that they could convict on one or the other, if they find him guilty.

Guy Rivera, charged in the fatal shooting of NYPD Officer Jonathan Diller, is pictured during his trial at Queens Criminal Court on Wednesday, April 1, 2026. (Gregory P. Mango / Pool)
Guy Rivera, charged in the fatal shooting of NYPD Officer Jonathan Diller, is pictured during his trial at Queens Criminal Court on Wednesday, April 1, 2026. (Gregory P. Mango / Pool)

Murder 1 carries the possibility of life without parole, while the aggravated manslaughter charge has a 25-year maximum sentence.

Intent still factors into the aggravated manslaughter charge, with the judge telling jurors they would have to find that Rivera wanted to cause serious bodily injury to Diller.

Rivera faced the attempted murder for allegedly trying to shoot Rosen, plus two counts of criminal possession of a weapon — one for the gun that killed Diller, the other for a loaded gun in the car’s glove compartment.

Deliberations continued into the evening Wednesday.