A Narre Warren teenage girl was killed in the three car collision in Rowville on Sunday at about 12pm.
Investigators believe the three vehicles were travelling north-bound on Stud Road before crashing near Kelletts Road.
The 17-year-old backseat passenger of a white Holden Calais sedan died at the scene and six people were hospitalised with minor injuries.
The Calais came to rest against a power pole near the intersection of Lakeside Boulevard.
The driver of the vehicle, a 28-year-old Clyde North man along with his 27-year-old female passenger and four-year-old boy were taken to hospital with non-life threatening injuries.
The sole occupant of the white Holden Commodore wagon, a 27-year-old Pakenham man was arrested at the scene.
Both drivers have been interviewed by police and released pending further enquiries.
A 19-year-old Narre Warren woman driving one of the vehicles with a male passenger was also taken to hospital with non-life threatening injuries.
She was interviewed on Monday and released pending further enquiries.
Witnesses have reported that at least two of the vehicles were drag racing.
The exact cause of the collision is yet to be determined and the investigation is ongoing.
Investigators are keen to speak to anyone who may have witnessed two of the vehicles, the white Holden Commodore wagon and the silver Holden Commodore sedan travelling on the Monash Freeway (inbound) before exiting at Stud Road prior to the collision.
The exact cause of the collision is yet to be determined and the investigation is ongoing.
Anyone with dash-cam footage or information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au
