The aunt of a pregnant woman allegedly killed by a teenager driving a stolen car has made a desperate plea for tough youth offending laws, remembering her niece as “everything that’s beautiful in this world”.

Danielle Leadbetter made the comments at an intersection in Brisbane’s Alexandra Hills where Kate Leadbetter, 31, and partner Marry Field, 37, were fatally hit by an allegedly stolen Land Cruiser.

Over 50 people gathered on Wednesday night to pay tribute to the couple, with well-wishers lighting candles and laying flowers at the roadside vigil.

Police claim the Land Cruiser slammed in a truck at speed before crashing into the couple, who were walking their dogs.

A 17-year-old alleged to be the one driving the 4WD, attempted to flee on foot but was later apprehended.

He has since been charged with the couple’s murder and a number of driving offences.

He may be facing a third degree murder charge over the death of the unborn child, police say.

Danielle Leadbetter said her niece, Kate, was “everything that’s beautiful in this world”.

“I remember Kate as my flower girl,” she told reporters alongside the roadside vigil.

“That was my nicest memory of Kate.

“And it’s hard to believe that someone doing such a selfish act could take someone’s life.”

Ms Leadbetter demanded Queensland Premier Annastacia Palaszczuk reform youth justice punishment “so young offenders aren’t let out on bail and they can not go and leave families traumatised”.

The woman’s comments follow reports the teen was out on bail for driving offences at the time of the crash on Australia Day.

“Enough is enough,” Ms Leadbetter continued.

“It’s 2021 and here we are again — two young lives are lost for a moment of thrills.

“Queenslanders need to get mad.

“No more loss of lives and no more families being killed because young offenders want a moment of fame.”