(CNN) Australian police boarded the Ruby Princess cruise ship Wednesday night to gather evidence for an investigation into how thousands of passengers were allowed to disembark in Sydney last month resulting in a spike of coronavirus cases.
Over 600 cases and 15 deaths have been linked to the ship, according to public broadcaster ABC.
Last week, police launched a probe into just why the Ruby Princess was allowed to dock in Sydney, dropping off 2,600 passengers, despite widespread concerns over coronavirus and multiple previous outbreaks elsewhere in the world involving cruise ship.
New South Wales police commissioner Mick Fuller said Wednesday that the ship's captain was "extremely helpful," and that the black box, a recorder similar to that found on airplanes, was recovered along with other evidence.
Officers went on the ship under the powers of the NSW coroner who has started a preliminary investigation.
It is expected that the investigation will involve interviewing thousands of witnesses, including the ship's captain, doctors, crew members, and passengers, and officials from the federal and state government.
"After reviewing the information at hand, the only way I can determine whether our national biosecurity laws or our state laws were broken is through a criminal investigation," Fuller said last week.
That investigation is running alongside the probe being conducted under the auspices of the coroner's office.
Fuller said Wednesday police were waiting for a human health report before deciding next steps and that report would be central to the investigation. He could not give a time frame for the investigation.
More than 1,000 crew members remain on the ship and Fuller says 75% have said they'd like to remain on the ship.
Late last month, Australian authorities publicly requested that all passengers who disembarked the ship self-quarantine, as they may have been exposed to the virus while on board.
The coronavirus pandemic has been devastating for the cruise industry, with outbreaks onboard vessels in the US, Japan and South America. While operators have halted most of the global fleet, more than a dozen cruise ships have been effectively trapped at sea, as countries refused to allow those carrying infected passengers to dock.
Australia's Department of Foreign Affairs and Trade said this month it was in direct contact with 10 cruise ships with around 600 Australian passengers on board.
"In most cases, disembarkation cannot occur unless passengers have onward flight arrangements and are able to travel directly to the airport via a so-called sanitary corridor, put in place by host countries," DFAT said in a statement.
On Thursday, Australian and New Zealand passengers on board a cruise ship stuck off the coast of Uruguay began being evacuated back to Australia. European and US passengers on the vessel, where 60% of passengers have tested positive for coronavirus, are still awaiting arrangements to take them home.