security guard coronavirus outbreak
(Image: AAP/Scott Barbour)

There's one question Victoria Premier Daniel Andrews just won't answer: why his government decided to appoint security firms rather than the army or police to guard travellers in quarantine -- a misstep thought to be a major factor in COVID-19's renewed spread through Melbourne.

We think we know why.

An Inq investigation into private security firms reveals the government has been acutely aware of the industry's record of dodgy behaviour going back to at least 2015, but it and the industry have failed to rein it in.