Homicide detectives are investigating a horrific crash that killed three people when a stolen car allegedly rammed another vehicle and forced it into the path of oncoming traffic.

The 25-year-old male driver of the stolen car is the only survivor and remains under police guard in hospital following the three-car collision on the Bruce Highway north of Brisbane about 4am on Friday.

It’s now been revealed the man was in a relationship with a 25-year-old woman who died in the pile-up.

The car had been stolen 12 hours earlier in a violent daylight carjacking in Gympie’s main street.

An alert for the vehicle was issued after a man allegedly threatened a mother and three children at knifepoint as the family was getting into the Isuzu MU-X.

The terrified mother got the kids out of the vehicle before handing it over to the robber. She and the children were unharmed.

Queensland Police later spotted the stolen car but the driver refused to stop and escaped. It was not being pursued at the time of the accident.

The stolen car was following and attempting to ram a northbound Nissan Navara, which veered onto the wrong side of the road at Federal, south of Gympie, and into the path of an oncoming Great Wall vehicle.

The 65-year-old male driver of the Navara and the 25-year-old female passenger died in the crash, along with the 38-year-old woman driving the Great Wall.  

The driver of the stolen car, who is known to police, was taken to Gympie Hospital and then to Sunshine Coast University Hospital with serious head injuries.

“Police can confirm the 25-year-old Yandina man was in a relationship with the 25-year-old Yandina woman who died in the crash at Federal,” the force said in a statement.

The 38-year-old female in the Great Wall vehicle was not known to any person in those other two vehicles.

The man is so far facing one count of robbery with violence whilst armed over the stolen car and is scheduled to appear in the Maroochydore Magistrates Court on Monday.

Detective Superintendent Ben Fadian said the investigation was complex and appealed for anyone who saw the stolen Isuzu on the Bruce Highway between Federal and the Noosa turn-off between 3am and 4am to contact police.

“The tragedy is that there are three people now deceased and the ripple effect that has on their families,” Det Supt Fadian said.

Queensland Ambulance Service’s Sunshine Coast acting director Nigel Jones said it was a confronting incident.

“The scene was obviously quite confronting given the mechanism of the forces involved – it was clearly a very high-speed incident involving those vehicles,” Mr Jones said.

“Our paramedics report that the two patients were killed on impact, with a third patient, unfortunately, passing away shortly afterwards.”

The forensic crash unit is also investigating.