Victoria’s descent into a new wave of infections, which has recorded more than 300 deaths and 16,700 confirmed cases, started amid a scandal over quarantine and security breaches in a series of Melbourne hotels.

Last month, Melbourne’s quarantine hotels were identified as a key source behind the virus’ terrifying escalation throughout the state which is currently at the beginning of a parliamentary inquiry.

In a special investigation on Monday, ABC’s Four Corners has exposed some of the conditions return travellers were put into upon arriving at some of the hotel quarantine facilities. Since March, all travellers returning from overseas have been made to isolate for 14 days in their hotel rooms.

Speaking to the program, one guest who stayed at Rydges on Swanston in April said the conditions within the hotel room were “dirty”, and that guards were not adequately protected while on duty.

“There were a couple of rooms that had bedbugs,” the guest, Christine Cocks, said.

“The guards that didn’t have their gowns on would be wearing gloves and masks. But that doesn’t necessarily protect you. If you rub your face with a gloved hand and then after the glove is off, you scratch again, put it in your mouth, near your nose – you’re away. There goes your infection.”

It is being argued at a parliamentary inquiry that a scandal over quarantine and security breaches in a series of Melbourne hotels is what helped create the city’s predicament today – putting millions of Australians in stage 4 lockdown and hundreds losing their lives to the virus.

As part of the investigation, Four Corners concluded the first case at Rydges was in fact a hotel staff member – not a guard as first thought. It is understood the worker completed cleaning jobs in the hotel. But within weeks, the initial case had spread to security guards working at the hotel, who were employed by private firm Unified.

Several insiders said the use of private subcontractors, including Unified Security, were employed without medical training to run the system. This meant hired staff were not properly briefed on their role, or given personal protective equipment, and did not take the job as seriously as they should have.

One security guard, named Peter, told the investigation that he was not told any detail about COVID-19 prior to starting his role at the Novotel on Collins in April, saying everything he knew about the virus he’d learnt “from television”.

Peter, who didn’t want to be identified, said he felt unsafe because quarantine guests were ushered past him while going to their rooms – without masks or protective equipment.

“They don’t have any protective gear; they don’t have a mask. And they’re not far from more than one foot from us,” he said.

“I have a family waiting for me at home … I don’t want to pass this disease on to them.”

In stunning video and photographs obtained by Four Corners, guests staying at an undisclosed hotel filmed unidentified guards sleeping on the job.

The investigation, which will be aired on the ABC at 8.30pm on Monday, the same day as the public inquiry into Melbourne’s bungled hotel quarantine began. Counsel Assisting, Tony Neal QC, confirmed the evidence over the next two days will reveal more about how the current outbreak can be traced back to overseas travellers quarantined in hotels.

He said the fundamental question to be examined by the board of inquiry was who was running and who was accountable for the program.

Unified Security, the company contracted by Rydges Hotel, have hired a lawyer to appear before the inquiry.

Rydges and Melbourne Hotel Group are also legally represented along with a number of government departments.

The hotel quarantine system did not include a frontline role for the Australian Defence Force nor Victoria Police, instead deciding to engage private security firms to guard the hotel occupants.

The inquiry will seek to answers questions like who was actually running and accountable for the program, as well as what would have made it work better, whether staff had appropriate access to personal protective equipment, and how the “huge demand” of a 14-day, 24/7 quarantine affected the people who were detained and those guarding them.

The full investigation, titled The Second Wave, will air at 8.30pm AEST on ABC