An innocent bystander gunned down at a pub during a family-friendly boxing event was happily singing Justin Bieber songs in the car just hours before tragedy struck.

Vana-Reese Schuster-Togiatau, 19, remains in a critical and unstable condition in Brisbane's Princess Alexandra Hospital after she was shot in the head and neck at Fitzys Loganholme pub, south of Brisbane on Saturday night.

Police said three men were also wounded after at least six bullets were fired from the front passenger window of a Mitsubishi ASX, which was later dumped and set alight in nearby Waterford West.

Inside, the venue was reportedly packed with young families attending the Logan City Titles Fight Night.

Just hours before the shooting, Ms Schuster-Togiatau uploaded a video to TikTok. 

The 15-second clip showed the carefree teen sitting in the back seat of a car with her boyfriend, lip-syncing to the Justin Bieber hit Daisies while enjoying pre-mixed drinks.

The video has since been inundated with dozens of messages from well-wishers.

'Wishing you a speedy recovery. All of Australia is behind you,' one wrote.

Another added: 'Praying for your recovery and healing for you girl.'

Two masked men suspected of involvement remain on the run as Ms Schuster-Togiatau fights for life in intensive care after undergoing emergency surgery.

It is understood the teen was not an intended target. 

'Her family is distraught,' Queensland Police Chief Superintendent Mel Adams told reporters on Monday.

'The families of the other victims are distraught.

'The wider community is questioning how can this happen in Logan?

'That’s a popular local pub, a well-respected institution. That location had children, teenagers, mums and dads at that sporting event.

'And that’s a well-known sporting event. It happens all the time in that location. Boxing events happen all around the state.

'It’s a legitimate sport and people should be able to go there and enjoy their time with their families in that sporting environment.'

Police have yet to establish a motive for the shooting but said elements of pre-planning suggested it was not random. 

Taskforce Maxima, a specialist Queensland Police squad that investigates outlaw motorcycle gangs and serious organised crime, is assisting local detectives and the State Crime Command in the investigation.

'I can tell you we will solve this crime. We absolutely will,' Chief Supt Adams said.

'But to do that, we need community input and we need community support.

'I wouldn’t use the term targeted, but there were elements of pre-planning that lead us to say it was not random.'

She pleaded for anyone with information, regardless of how small, to 'step up' and come forward.

'This could have been your family member,' Chief Supt Adams said.

'This was a random group of people at the front of a popular hotel who became victims. 

'So if you know something, help us with this investigation.

'It could be the smallest thing. You are not sure if you want to tell us about it because it could be nothing. 

'In isolation it might seem like nothing, but when you tell us, it adds to quite a comprehensive and growing intelligence picture and we need that information from you.'

It comes as Phil Austin, from the Australian National Boxing Federation Queensland, categorically rejected suggestions that the boxing meet was targeted by bikies or organised crime.

He told the Daily Mail that speculation linking the boxing event to bikies and organised crime was 'people putting two and two together and getting five'.

'I haven't seen any reputed organised crime figures at a fight show in this country in years,' he said.

'Bikies used to go to events, but since the government changed their laws, you just don't see them.'

Mr Austin said he did not recognise the wounded victims and could not say whether they were there for the boxing.

'I don't even know if they were there to watch the boxing,' he said. 

'There's more than just boxing happening at that pub.'

'We have no idea why what happened happened. The only thing that we know for sure is it's a tragedy.'