The Toyota driver “may have been” involved in a dispute with the driver of a white Audi A3, Harpur said.
The Audi driver was seen leaving Horsham Downs Primary School about 10am. The Toyota was close behind.
Both vehicles were travelling “at speed” and were overtaking each other, police understood.
As the vehicles sped up Boyd Rd, the Toyota driver tried an overtake and it collided with an oncoming Mazda, killing the Mazda’s driver.
Harpur asked anyone who witnessed the incident or any dangerous driving on Boyd Rd or Williamson Rd between 9.45am and 10.15am to come forward.
“We would like to hear from those with dashcam footage, security footage, or other imagery of vehicles driving dangerously on those roads between those times,” he said.
“If you can assist, please make a report via our 105 service, referencing the file number: 240627/4717.”