Police have seized a car linked to a fatal hit-and-run in inner Brisbane that killed a 20-year-old woman on her birthday.

Ashleigh Humphrys was walking home after celebrating when she was struck near the Toowong roundabout about 3:50am Sunday.

Security footage shows a dark sedan mounting the footpath and swerving back onto the road.

• Man charges with Qld murder
• Twist in Qld cold case murder
• Father dies after road rage fight in Qld

Officers will not reveal if they have seized that car.

“We’ve seized a vehicle, which is currently undergoing scientific investigation,” a police spokesperson said.

“The owner is assisting police with their inquiry.”

Senior Sergeant Simon Lamerton said Ms Humphrys was either lying on the road or on her hands and knees when the accident happened.

“The injuries are consistent with that,” he said.

He said people had tried to put Ms Humphrys into a cab at a nearby Caltex service station but she had walked away.

“It looks like she certainly has been intoxicated,” Senior Sergeant Lamerton said.

“It appears from the CCTV footage Ashleigh was walking towards the Western Freeway on the inbound side … she walks just out of view of the CCTV then a taxi stops just past where she was last seen and was stationary for a number of minutes.

“Some other cars have filtered through at fairly low speed … and then a dark coloured sedan has come through at a slightly higher speed.”

Senior Sergeant Lamerton said a taxi that was first on scene had earlier been seized as part of the investigation, but there was no evidence of it being involved in Ms Humphrys’ death.

He said a second taxi may also have been at the scene – off to the side for a short time, away from the first taxi.

“If that driver could come forward to help us just to rule them out,” he said.

“The footage is not of great quality and is from a distance – [it] may not even be a taxi.”