The NYPD police officer who shot an unarmed man in a Brooklyn housing development texted his union representative as his victim lay dying, it has been claimed.

After Peter Liang shot Akai Gurley on November 20, he and his partner Shaun Landau were in communication for more than six and a half minutes.

During this time Liang's superior officer and an emergency operator who had fielded the 911 call about the shooting, tried in vain to reach the rookie policemen.

Scroll down for video

Tragedy: The officer who killed young father Akai Gurley (above) in Brooklyn told his partner 'I think I'm going to get fired' seconds after the fatal shooting

Accident: Officer Peter Liang claims he was holding a flashlight and had his gun drawn when he accidentally fired, striking Gurley in the chest while the young man was in a darkened stairwell (above)

Scene of the crime: It all happened at the Louis Pink Houses (above) in the East New York section of Brooklyn

A source told the New York Daily News that Liang's behaviour showed 'negligence'.

He said: 'The guy is dying and you still haven't called it in?'

The officers were also uncertain of their exact location, the newspaper reported, something that further hampered emergency services response to the death.

The details of what happened in the aftermath of the shooting are at the centre of an investigation by Brooklyn District Attorney Kenneth Thompson. He is expected to present evidence to a grand jury as early as the end of this month, but has already called the death 'deeply troubling' and has promised a 'thorough investigation'.

Gurley, 28, was pronounced dead at Brookdale Hospital shortly after the shooting and his death has been ruled a homicide. He is to be laid to rest tomorrow.

His mother, Sylvia Parker, and stepfather, Kenneth Palmer, are scheduled to make their first public statements today.

Left behind: Gurley was the father to a two-year-old daughter, Akaila, seen above

Liang and Landau were not supposed to be patrolling near the the stairwells of the housing block when the shooting occurred. Instead police chiefs had called for officers to stick to exterior patrols - so officers could be seen on the beat - following a spike in violent crime in the area.

The shooting happened after Liang opened a door while holding a flashlight in his right hand along with a Glock 9-mm.

The gun fired and hit Gurley in the chest as he walked with his girlfriend Melissa Butler, 27, some 12 feet below the officer.

Liang was then said to have told Landau, 'I think I'm going to get fired', before he had even noticed that the bullet had ricocheted and hit Gurley. It wasn't until the men saw Butler sobbing over her boyfriends body that they realised what had occurred.

Justice: Now, the Brooklyn district attorney's office is launching an investigation into the shooting as friends and family mourn Gurley's death (above)

Butler then ran to a neighbour's and called 911 saying she 'feared for her life'. When the two officers returned to radio communication they reported an accidental discharge.

Lt. Vitaliy Zelikov, who arrived on the scene in the aftermath, said Liang was 'visibly upset, shaken up and clearly very distraught'.

On Monday, Butler met with the DA Thompson. He had also met with community leaders on Sunday after more than 250 people marched in protest outside Liang's 75th Precinct the day before calling for justice.

The Internal Affairs Bureau of the NYPD has also launched an investigation into the shooting of Gurley, Commissioner Bill Bratton called a 'total innocent.'