Mourners gather for funeral of slain NYPD cop Jonathan Diller, 31, after he was gunned down by 'serial criminal' - as thousands of police officers from across the country line the streets to pay their respects

Slain policeman Jonathan Diller is being mourned at a funeral attended by thousands of cops from around the country.

The NYPD officer was gunned down in Far Rockaway, near JFK Airport, on Monday, allegedly by career criminal Guy Rivera.

Diller, 31, is receiving a police funeral at St Rose of Lima RC Church in Massapequa, on Long Island, that began at 10.30am today.

Once the Catholic funeral service is over, Diller's coffin will be covered in the green and white NYPD flag and carried out of the church by uniformed pallbearers.

They will place it in the back of a hearse and fold the flag into a triangle, handing it to Diller's widow Stephanie Diller.

Hundreds of police motorbikes will lead a funeral procession through the streets to the cemetery where Diller's body will be laid to rest.

A police bagpipe troop will play as the hearse begins to leave the church, accompanied by drums draped in purple and black mourning cloth.

Thousands of officers will line the street and salute as the hearse passes.

Diller's body lay in a funeral home as mourners came to pay their respects, including former president Donald Trump, and New York Governor Kathy Hochul.

Trump sent a large bouquet of hydrangeas and red roses to the church, with a note reading: Thank you to Officer Diller for his service. Our prayers are with your family at this time.'

New York City Mayor Eric Adams, a former NYPD captain, will speak at the funeral and former mayor Rudy Giuliani arrived early to attend the service.

Former NYPD Commissioners Bernard Kerik and Keechant Sewell also attended, with Amazing Grace playing before the start of the service. 

Michael Duffy, the priest leading the service, married Diller and Stephanie in 2019 at Our Lady of Lourdes in New York City.

They have a one-year-old son, who is in attendance at the funeral.

Diller graduated form the State University of New York Maritime College with a degree in marine transportation in 2014, then joined the NYPD in February 2021.

He was recognized for 'excellent police duty' three times since joining the force. 

Diller's funeral has been relentlessly politicized, mostly by Republicans who used it as an opportunity to accuse Democrats of being soft on crime.

Trump attended the officer's wake, where he slammed Joe Biden for not attending the wake even though he was only half an hour away.

He also accused his Democrat rival of not backing the police because his liberal supporters 'won't let him'. 

Diller was shot after he approached a car that was parked illegally in front of a bus lane, shortly before 6pm Monday.

After Rivera refused to roll down his window or show his hands, he allegedly opened fire on Diller, hitting the young officer under his bullet proof vest.

After Diller's partner returned fire, both Rivera and Diller were rushed to hospital. The officer was later pronounced dead and Rivera was in a stable condition.

Lindy Jones, who was behind the wheel of the car alongside Rivera, was charged with gun possession and possession of a defaced firearm.

Prosecutors said a search warrant was issued on the vehicle in the shooting, which uncovered a second firearm. 

He was held without bail as officials cited Jones' history of skipping court dates in the past.

Jones - who has a history of 14 arrests including a 10-year stint in prison on attempted murder from 2003 - refused to talk with detectives since his arrest on Tuesday night. 

Investigators believe Jones and Rivera had been casing out a T-Mobile store before the shooting.

Horrific surveillance footage captured the moment the young NYPD cop writhed in agony on the streets of New York after being shot.

Three loud gunshots can be heard ringing out as bystanders flee for safety. 

Despite being shot, Diller moved the gun away from the shooter after it was dropped on the ground, NYPD Chief of Detectives Joseph Kenny said during a press briefing. 

Following Rivera's arrest, it emerged that he has a lengthy criminal history including first degree robbery, illegal gun possession and assaults.

He had 21 prior arrests and previously served five years in prison on drug charges before being paroled in 2021.

He had also been incarcerated from 2011 to 2014 over a first-degree assault charge.

Jones had 14 prior arrests, including a conviction for attempted murder and robbery in 2003 that saw him serve 10 years behind bars.

He had been arrested on gun charges last April but was released on a $75,000 bail that was set to bring him back to court Monday.

Following Jones' April arrest, where he was caught with a loaded firearm, Mayor Adams said that he was a prime example of a 'recidivist problem' - meaning a small number of perpetrators committing a large number of crimes.

'Same bad people doing bad things to good people,' Adams added.