A homicide probe has been launched into a crash that killed four people after investigators discovered evidence of another car chasing the ute before it veered off a quiet country road.
Police and members of the victims' families appealed to the public for information on Tuesday as details of the upgraded investigation were revealed nearly three months after the deadly crash in regional NSW.
Emergency services were called to Back Channel Rd at Wardell, south of Ballina on the NSW north coast, about 5.45am on February 24 following reports of a single-vehicle crash.
All four occupants of the blue Mazda BT50 were killed when it left the road on a bend.
Those killed were the driver, Mark Dodds, 36, and passengers Sophie-Lee Fullagar, 33, James Doherty, 42, and Benjamin Watego, 50.
Superintendent Scott Tanner said the crash was being treated as a homicide after CCTV footage showed a second car in the area moments before the fatal incident.
"There was a second vehicle involved in that accident, which is an early 2000s silver Toyota Corolla sedan," he said.
"We believe that vehicle was chasing the Mazda BT50."
Vision released by police shows the Corolla closely following the ute as it travelled over a bridge before the crash.
Police are appealing to the local community for information about the second vehicle.
"We believe there are people in the community that know who was involved in this and we are urging them to come forward," Supt Tanner said.
"Investigators are following all leads at the moment."
Four families had been left searching for answers after the deadly crash took away their loved ones, Supt Tanner added.
"Their trauma has now been exacerbated due to the nature of what we now believe is homicide," he said.
Ms Fullagar's mother Rebecca urged those involved in the incident to contact police.
"My daughter was an innocent victim in this and she deserves justice," she said.
"They all deserve justice because they were all people, they all have families."
