A man was airlifted to hospital following a crash at Hilldene on Saturday, November 8.
Emergency services were called to Seymour-Tooborac Rd after a car crashed into a tree about 2.35pm.
Police said the sole occupant of the vehicle was a man in his 60s.
He was airlifted to hospital with serious injuries.
The investigation remains ongoing, and investigators hope to speak with anyone who may have witnessed the crash as they work to establish the circumstances surrounding the incident.
Anyone who witnessed the incident or has dashcam footage is urged to contact Crime Stoppers on 1800 333 000 or visit crimestoppersvic.com.au