Jye McWatters was safe in his bed in the early hours of Boxing Day. He told his grandmother and his 14-year-old brother he loved them before he turned in.

Hours later the 19-year-old lay lifeless on his Kippax Street front lawn, to be discovered about 1pm.

Dwayne McWatters found his brother with a bleeding wound to his head. 

“[A younger brother] said, ‘here’s Jye’, thinking he was asleep,” Dwayne McWatters, 25, told the Mercury.

“I rolled him over. He was stiff as a board.

“He was the biggest piece of my heart … he was my shadow.”

Trish Gallastegui does not believe her nephew’s death was an accident. 

She queries why the teen – known for his fondness for “good clothes” – had no shoes on when he died.

“If he was going out somewhere, he’d never be seen looking like a bum,” she said. 

“He’s come out the front, not expecting to leave [the property].

“Police have asked [Jye’s grandmother], ‘didn’t you hear anything?’. 

"Whatever happened, happened quietly.”

NSW Police initially described the death as unexplained.

Ms Gallastegui watched police examine the yard on Boxing Day. 

She said they returned in greater number the following day, bringing police dogs, and combing the grounds for clues. 

“We think they got some information between Boxing Day and then,” she said, Tuesday morning.

“Something seems to have changed, but they won’t tell us what.”  

Late Tuesday, strike force detectives confirmed a post mortem examination had determined Mr McWatters had suffered a gunshot wound.

Police have formed Strike Force Briony – a combination of local police and detectives from the State Crime Command’s Homicide Squad and the Southern Region - to investigate the death.

Mr McWatters' close friends have since spoken with police in an attempt to piece together his final hours. 

Fairfax Media understands Mr McWatters had been involved in a dispute with a teenage boy before his death.

The situation escalated to a point where police earlier this month applied for an apprehended personal violence order (AVO) to protect Mr McWatters and his grandmother from the teenager, who can't be identified due to his age.

The AVO application was scheduled to be heard in Port Kembla Children's Court next month but an interim order was put in place on December 7. 

The teen, from the Illawarra area, was ordered not to assault, threaten or harass Mr McWatters and not go within 100 metres of his home. 

However police aren't treating the dispute as a strong line of inquiry at this stage.

Detectives have interviewed numerous teens who attended a Christmas Day party with Mr McWatters at a friend’s house on a nearby street.

Mr McWatters said goodnight to family shortly after returning home from that gathering.

Friends have paid tribute to the “loyal” teen, who was “always looking out for people”. Ms Gallastegui said her nephew was “the class clown”.  “He was a bit of a ratbag, but he had a good heart,” she said. “He was a family person. He always had a big smile on his face. He thought he was invincible, like all boys that age.”

Mr McWatters’ family is calling on anyone with information that could aid the investigation to contact Crime Stoppers: 1800 333 000.