NYPD Det. Jonathan Diller's widow, Stephanie, provides emotional testimony at murder trial of husband's accused killer

Just before he was unexpectedly called in to work on his day off March 25, 2024, NYPD Det. Jonathan Diller spent what was left of his quiet morning with his wife, Stephanie, having a cup of coffee and then taking a stroll with the couple’s 1-year-old son, Ryan, at a park near their home In Massapequa Park.

"I love you," officer Diller, 31, told his wife before driving to his job as a community response team officer in Queens.

"I love you too, “ Stephanie Diller said she replied, as she recounted that day on Thursday in Queens State Supreme Court. She testified in the trial of Guy Rivera, the man accused of taking her husband's life during a fateful encounter in March almost two years ago.

Struggling to maintain her composure and her voice close to sobs, Stephanie Diller recounted for jurors the terrible day she lost the man she portrayed as the love of her life.

Diller told the jurors how the couple’s idyllic family life began to shatter after she learned from a friend that an officer had been shot in Queens, and how her heart sank after she noticed her spouse’s cellphone was not on a Queens street or in his office but at Jamaica Hospital Medical Center.

A call from a friend of her husband confirmed the worst: Jonathan Diller had been shot.

"How bad is it?" asked a fearful Stephanie.

"It is bad," the friend replied.

NYPD officials then helicoptered Stephanie Diller, who works for Good Samaritan University Hospital in West Islip, from Nassau County to Queens, where she learned the terrible news, she recalled for jurors.

On Thursday, after testifying for about 10 minutes, Stephanie Diller, 31, left the courtroom along with family members. 

Earlier in the day, Dr. Robert Liskowski, a top trauma surgeon, testified he and a team had worked feverishly to save Diller. He recalled how he was the one who had to break the news to the officer's wife that her husband did not survive. 

"Is he dead?" Liskowski remembers Stephanie Diller asking at the hospital.

"Yes, I am sorry," Liskowski testified he responded.

Liskowski, who also serves as vice chair of surgery at the hospital, told the jury he knew almost instantly Diller had suffered a mortal wound. 

The surgeon described in graphic detail how he slit open Diller’s chest with a scalpel, pried his chest bones apart and then began to massage his heart. Others on the medical staff then started to pump blood into Diller, who had lost three or four liters.

During Liskowski's testimony, the prosecution showed a picture of Diller on the operating table, an image that drew gasps from some of the police officers in the courtroom.

Liskowski's efforts revived a heartbeat for Diller, and he took him up to an operating room where the heart stopped again but was revived a number of times. About 50 units of blood had been given to Diller, he told jurors.

But the loss of blood and oxygen put Diller on an irreversible slide, and he was pronounced dead at 8:10 p.m. on March 25, Liskowski said.

Liskowski said he took a moment to walk around the operating room and collect his thoughts before he finally went to see Stephanie Diller to break the terrible news.

Rivera, who was also shot by police during the encounter, was also treated at Jamaica Hospital. Liskowski said he briefly attended to Rivera, who was handled by another medical team.

The testimony of Stephanie Diller and Liskowski capped the third day of testimony in the trial, which began Tuesday.

Rivera, who served time in prison for firing a weapon at someone in 2011, was indicted on first-degree murder and other charges in Diller's death.

According to police, Diller was part of an NYPD community response team patrolling near 19-19 Mott Ave., in Far Rockaway.

Diller and fellow officers, including Sgt. Sasha Rosen, spotted Rivera, now 36, leaving a store around 5 p.m. They noticed he appeared to have a bulge in the front pocket of his sweatshirt and followed him to a parked 2016 Kia Soul. According to police, after Rivera entered the passenger side front seat, the door was locked and Diller tried to open it after asking Rivera to unlock it. In the driver’s seat was Lindy Jones, 43, who had a conviction for attempted murder. Jones is being tried separately.

Then, according to investigators and court records, Rivera fired one shot at Diller with a .380 mm semi-automatic pistol, striking the officer in the abdomen, just under his protective vest. Surveillance camera video captured a mortally wounded Diller writhing in pain on the ground.

"I’m shot!" Diller could be heard saying on police body camera footage before being taken to a hospital, where he died. At his funeral, Diller was promoted to detective.

Queens State Supreme Court Judge Michael Aloise said the trial would resume Monday.