A man was sentenced to 115 years in prison on Monday for the fatal shooting of a New York City police officer who had ordered him to step out of a car in Queens in 2024.

More than 200 people, mostly police officers, packed a courtroom in State Supreme Court in Queens to hear Justice Michael Aloise sentence Guy Rivera in the killing of Jonathan Diller, 31, who was promoted to the rank of detective after his death.

“It took me five minutes to calculate these numbers,” Justice Aloise said. “It’s going to take you a lifetime to calculate the damage you did and the grief that you caused.”

He said that Mr. Rivera had determined his own fate “the second you pulled that trigger.”

Detective Diller’s wife, Stephanie, who sat among the officers in the courtroom, read a statement in court just before the sentencing, speaking of the pain and loss that she and her son, Ryan, now 3, have suffered. Ms. Diller, who testified during the trial, spoke directly to Mr. Rivera as he sat at the defense table.

“This is the last moment I will allow you to take from me,” she said as tears rolled down her cheeks. “You took my husband, Jonathan. You took the future we planned together. The life we were building, the years we were supposed to share together.”

“What you did to Jonathan” she said, “gave me and our son a life sentence without him.”

A jury found Mr. Rivera, 36, guilty earlier this month on four charges, including aggravated manslaughter, in Detective Diller’s death, but acquitted him of the most serious charge, first-degree murder. The decision, after a three-week trial in Queens, stunned the dozens of police officers present when it was announced in the courtroom on April 1.

To find him guilty of murder, the jury had to decide whether they believed Mr. Rivera had intended to kill Detective Diller when he pointed his gun at him in the Far Rockaway section of Queens on March 25, 2024. They ultimately determined that Mr. Rivera had intentionally pulled the trigger, but did not intend to kill him.

Mr. Rivera did not speak at his sentencing at the advice of one of his lawyers, Jamal Johnson, who told Justice Aloise they would appeal the conviction.

Mr. Johnson, a lawyer with the Legal Aid Society, said after the hearing that Justice Aloise’s statement at sentencing showed the court “had already made up its mind about sentencing well before the trial was conducted.”

During the trial, prosecutors said that before the fatal shooting, Detective Diller’s partner, Sgt. Sasha Rosen, saw Mr. Rivera and another man, Lindy Jones, come out of a store and get into a car. Mr. Rivera had an L-shaped object in the pocket of his sweatshirt that resembled a firearm, prosecutors said.

Detective Diller approached the vehicle and asked Mr. Rivera repeatedly to comply with orders. When he did not, Sergeant Rosen reached in to pull him out of the car.

Then Mr. Rivera fired, the jury found. The defense argued that Mr. Rivera’s gun went off accidentally when Sergeant Rosen pulled him out, striking Detective Diller. Prosecutors said Mr. Rivera then turned his gun on Sergeant Rosen, but the weapon jammed.

Justice Aloise did not allow the jury to see video that, the defense contended, showed Mr. Rivera’s arm was broken during his confrontation with the police.

That evidence would have directly undermined the prosecution’s contention that Mr. Rivera was physically able to pull the trigger when he tried to shoot Sergeant Rosen, they said.

In all, Mr. Rivera was sentenced to 25 years to life for the aggravated manslaughter conviction; 40 years to life for the attempted murder of Sergeant Rosen; and 25 years to life for each of the gun possession counts. He was ordered to serve those sentences consecutively.

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On Monday, after the sentencing, dozens of police officers smiled and embraced one another as they left the courtroom. The prosecutors who tried the case and Melinda Katz, the Queens district attorney, hugged several of Detective Diller’s family members.

Jessica Tisch, the police commissioner, called the sentence “obviously the right result, for him and for anyone who kills a New York City police officer.”

Outside the courthouse, members of the Police Benevolent Association, the police officers’ union, said they were pleased with the sentence.

“The verdict in this case did not send the right message to the Diller family and every police officer who wears the uniform,” said Patrick Hendry, the union president, who spoke at the foot of the courthouse stairwell, backed by nearly 100 police officers.

“But this sentence,” he said, “it sent the right message.”