Kullar said no arrests have been made at this stage, but police are making inquiries into the circumstances of the incident.
They would also like to hear from any residents in nearby apartment buildings who may have filmed the incident, or part of it.
Police at the scene were unable to comment, but the Police Eagle helicopter was circling above.
While police guarded the Nelson St car park, about a dozen officers descended on Queen St and armed police pulled over a Toyota Hiace van as part of its inquiries because it was in the area at the time of the shooting. The occupants were then seen to be handcuffed by police.
At the same time several police staff and an ambulance were also on Victoria St West between Federal St and Albert St as part of the response to this incident.