A former police officer is at the centre of investigations into a horror Brisbane crash that killed him and a young woman.

Another woman was left in a critical condition after Wednesday’s crash in Brisbane’s Legacy Way Tunnel, amid reports that the Audi driven by former officer Bruce Daley hit speeds of up to 200km/h in the moments before.

Police said the black Audi S3 was travelling north when it hit a silver Mazda sedan, which then hit a small truck, in the city-bound lanes of the tunnel at Mount Coot-Tha about 3.10pm.

Daley, a 56-year-old former Queensland police officer from the Gold Coast, died at the scene along with a 24-year-old Darwin woman who was a passenger in the sedan.

The Mazda driver, a 23-year-old woman from Adelaide, had surgery and was in a critical condition, Inspector Steve Crabbe said on Wednesday night.

The 45-year-old driver of the white van was taken to hospital with non-life threatening injuries.

Police have appealed for information about the Audi S3 as they to investigate the cause of the crash.

“The scene was over several hundred metres and involving three vehicles – and obviously extensive traffic delays were involved,” Crabbe said.

One witness has told The Courier-Mail the Audi was being driven at speeds of more than 200km/h seconds before it hit the sedan.

“I was driving behind the Audi … for some reason [the driver] slowed down and stopped when we entered the tunnel,” they said.

“Then I could hear a car engine roaring as he went past me … then 20 seconds later smoke and debris was flying around.”

Detective Acting Inspector Chris Hansel said on Thursday the crash was a tragedy.

“Every life lost on our roads is a tragedy and we continue to implore drivers to practise patience,” he said.

Hansel said police were examining footage from inside the tunnel and investigating all the vehicles involved.

“Speed is obviously being considered as a contributing factor,” he said.

He said it could be months before the investigation was complete and the cause of the fatal crash was known.

“These investigations are incredibly complex, they’re very challenging by nature,” he said.

“We have to have those answers eventually for those family members that are affected.”

Images of the crash were posted to social media on Wednesday. They show the Audi and silver sedan were destroyed.

All lanes of the tunnel were closed to motorists for more than two hours after the crash. The tunnel had reopened by Thursday morning.

-with AAP