Jozef Stefaniak, 24, the son of long-time Canberra Liberal and one-time party leader Bill Stefaniak, was thrown from the rolling car on January 2 and suffered fatal head injuries.

Police initially claimed it was Kane David Kell who was behind the wheel when the car lost control. He was arrested the next day and charged with failing to give assistance, speeding and culpable driving causing death.

But Mr Kell, 21, was released on bail the following week after prosecutors told the court fresh information had came to light. His girlfriend, Angela Lea Smith, 33, was later arrested and charged over the death.

As the charges against Mr Kell in relation to the fatal crash were withdrawn in one courtroom on Wednesday, Ms Smith appeared via videolink in the courtroom next door in a second bid for release.

In documents tendered in the ACT Magistrates Court for Ms Smith's application for bail, police allege Mr Kell had been driving when the couple fought and he pulled into a car park.

Mr Kell got out of the car, slammed the driver's side door a couple of times and sat on a nearby park bench with a dog.

A witness allegedly saw Ms Smith get out of the passenger side of the car, and a surveillance camera on a Transport Canberra bus also captured her movements, documents say.

The documents suggest that about 6.01pm the footage showed Ms Smith get into the driver's seat and Mr Kell get into the passenger seat.

At 6.04pm Ms Smith lost control of the white BMW before it rolled on Yarra Glen in Hughes, the documents allege.

Following what witnesses described as a "violent high speed crash", police say both Ms Smith and Mr Kell fled the scene without helping Jozef Stefaniak, who had come to rest on the grass median strip.

Witnesses allegedly heard Mr Kell yell out, "He's dead, he's dead" before he grabbed the dog and fled.

Ms Smith, who appeared in court on Wednesday via video link, made a second attempt at bail.

Jozef Stefaniak's parents Bill and Shirley were sitting in the public gallery for the bail hearing.

Prosecutors opposed Ms Smith's release on bail, citing fears she would reoffend, fail to appear at court and interfere with witnesses.

Defence solicitor Darryl Perkins said Ms Smith was keen to get out of prison partly to check on her Conder home, which she heard had been broken into while she was in custody.

He said that she had been taking steps to deal with issues of drug use.

But Magistrate Bernadette Boss refused Ms Smith bail, pointing to the woman's history of failing to appear at court and breaching bail which had both frustrated the justice process.

She noted too, prosecution concerns Ms Smith had tried to contact Mr Kell while they were both in custody in jail.

Ms Smith has not yet entered pleas in relation to the fatal crash. Those charges include speeding, culpable driving causing death and failing to give assistance, as well as not wearing a seatbelt, driving while unlicenced, drug driving and using an uninsured and unregistered car.

Earlier, and in the courtroom next door, Magistrate Beth Campbell granted a prosecution request to withdraw the charges against Mr Kell relating to the fatal crash.

But Mr Kell remained in custody in the Alexander Maconochie Centre after allegedly committing traffic offences while he was on bail in January.

Ms Smith is due back in court on February 26.