A young man celebrating his engagement was fatally shot hours later in a Thomastown car park, according to reports.

Daniel Hussein, 22, was found critically injured with a gunshot wound around 7:30 p.m. on Sunday and died at the scene. He was due to be married this year. Shortly before the incident, he reportedly sent a message to his family stating he was being followed by an unregistered black Porsche.

His uncle, Abdallah Hussein, shared a video of the engagement party on social media, expressing his grief. "I never imagined I would one day be sharing memories of you," he wrote. "More than 150,000 people have seen your story. Thousands have cried, prayed, shared and spoken your name."

According to Hussein's brother, Ali, Daniel had gone to help a friend who was involved in a dispute. "His friend got into a brawl and called my brother," Ali Hussein stated. "My brother pulled up (in his car) and they shot my brother. His car was still running."

Ali Hussein suggested the shooting may have stemmed from a dispute in Melbourne's CBD the previous night. He described his brother as a sensible young man who had recently completed his plumbing apprenticeship and owned his own home. "He’d come home from work and go straight to the gym - he was into his fitness," Ali said.

Police established a crime scene at the Thomastown reserve car park, which had been used for junior soccer matches earlier that day. Investigators cordoned off part of Victoria Drive, with multiple police cars present overnight. Apparent bloodstains were visible in the car park on Monday morning.

Some online comments have linked the shooting to Melbourne's gangland conflicts, but friends and family have strongly denied these claims. "People are quick at judging the situation when they don’t know," one person commented. "No-one should be taking no-one's life - they should be leaving this earth caused by illness."

A neighbor reported hearing screaming and yelling for several seconds before an SUV reversed out of the reserve's driveway. The neighbor stated that Mr. Hussein appeared to have jumped onto the vehicle, kicking its bonnet and headlights before falling to the ground as the car drove away. It was unclear at what point he sustained the gunshot wound.

Detectives are appealing for witnesses, or anyone with CCTV or dashcam footage, to contact Crime Stoppers on 1800 333 000.