Tributes have flooded social media and flowers have been laid at the crash scene where Tim Smith-Brown was killed after he sped through a red light on Drakeford Drive in Kambah on Friday evening.

The exact circumstances of the crash are still unknown. Police say they had terminated a high-speed pursuit of Mr Smith-Brown before he allegedly ran the red light and hit two other cars.

Three people in those two cars were injured and taken to hospital, where they remained in a stable condition over the weekend.

Mr Smith-Brown's pregnant girlfriend, Felicity Jessop, was a passenger and survived the carnage, albeit with serious injuries.

She was rushed to Canberra Hospital and has since given birth to a boy, who has been named after the father he was never able to meet.

A GoFundMe online fundraising page has now been set up to help her and the baby boy as they recover from the crash.

It had raised $705 for mother and son in 23 hours.

The organiser of the page, Samantha Hurley, told Fairfax Media that Ms Jessop was a positive, friendly person who had been her friend for years.

"You meet her and you instantly know she is just an awesome person, and I don't believe anyone deserves what has happened," she said.

"The money will be for little Tim! For a better start in life, make it less stress on the families as the poor bubba would feel it also."

The death provoked an ugly discussion on social media, where some appeared to suggest the fleeing driver deserved to die.

That prompted an angry response from many, including Mr Smith-Brown's father Warren Brown, who wrote on Facebook:

"The person in the red Ute did die. It was my son, you are a heartless individual.

"He [was] about to become a great father. He was an amazing son and loving caring person. Everyone makes mistakes."

Flowers were left at the scene of the crash, on Drakeford Drive, over the weekend.

Ms Hurley thanked those who had contributed to the fundraising page.

"I thank them all for still having an open mind and not being so judgmental," she said.

Investigations into the crash are continuing internally within ACT Policing.

Police said they tried to pull over the "vehicle of interest" about 5.45pm on Friday.

The car is alleged to have sped away from them, prompting a pursuit for a "short time".

Police say they terminated their chase some time before the crash, but the car continued at high speeds along Drakeford Drive, running the red light at the intersection with Marconi Crescent and Boddington Crescent, near the Kambah shops.