When Ed Robins noticed bruising and skin tears on his 92-year-old mother, he decided to install a small video camera in her room at Perth's Morrison Lodge nursing home.

The footage he captured over three weeks made for distressing viewing.

Mrs Robins had recently broken her leg and had worsening dementia. Often, she would wake up and, forgetting she could not walk, would try to get out of bed.

The hidden camera footage, provided to the ABC's Four Corners, captured the staff response.

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On one occasion, Mrs Robins was left lying on the floor for more than 20 minutes, calling for help.

The vision also shows personal carers pushing Mrs Robins down in bed by the head and shoulders, repeatedly forcing her head down as she puts her arms out to defend herself.

On another occasion, as Mrs Robins cried out in distress, they put a pillow over her face.

Another time, carers lifted her by the arms and swung her legs around with no warning, including the leg that had been pinned after it was broken.

"Mum was in pain, obviously, putting her hands up to protect herself, and they're throwing her leg in," Mr Robins said.

When they used a hoist to lift her, Mrs Robins was unsure what to do and looked scared.

"Don't give us a hard time!" One of the carers tells her.

On another occasion carers laugh in her face when Mrs Robins lashes out at them for grabbing her sore leg.

Ed Robins took the footage to Morrison Lodge who called Perth police. Two carers were charged with 12 counts of assault in relation to some of the incidents captured by the hidden camera.

Magistrate says carers run off their feet

In March this year, Magistrate Gregory Smith acquitted the carers of all charges. He found the carers were run off their feet and Mrs Robins was "often violent and abusive towards staff".

Magistrate Smith likened the situation to that of dealing with a difficult child:

"Perhaps if I were to give a quick example, placing of a two-year-old or a three-year-old into a car seat and trying to get their seatbelt done up," he said. "If that child is compliant, then some force is needed, but not much. If the child is resisting, then more force is needed. If the child is throwing a complete tantrum, then obviously extra force is needed to achieve what has to be achieved."

Magistrate Smith said some people might view the footage differently.

"I understand that some people might look at the footage that we've seen in court and think that perhaps or probably [one of the carers] should have used a little bit less force or it didn't look very good or perhaps with hindsight, she could have done something differently," he told the court.

"But even if I thought that myself, it would not be enough for a conviction."

He awarded costs to the two carers.

Mr Robins was shocked.

"What would you call it? I call it abuse," he said.

"She was being abused. There's different types of abuse. She has been physically abused, in our eyes, and from what we were told by the police."

Jean Robins on her wedding day. Ed Robins says one of the hardest parts of their ordeal was having to show the rest of the family the hidden camera footage. ( Supplied )

Four Corners spoke to current and former aged care workers who responded to the ABC's biggest crowdsourced investigation.

Many of them said they had witnessed similar scenes that they described as "rough handling".

"Rough handling to me can be as simple as rushing a resident," personal carer Melanie Whitely said.

"If you've got a resident that's got dementia and isn't understanding that you're undressing them to give them a shower, you can't just be ripping their clothes off here, there, and everywhere. They resist, they'll fight you, and it's rough."

Homes continue to receive accreditation despite complaints

Some personal carers have as little as six weeks of training to qualify them for work in the sector.

"There were some people that were clearly not suited to working in a care capacity. They were lacking in empathy and seemed unable to imagine what it would be like to be in the situation of a dependent, frail person," personal carer Tanya Bosch said.

When the regulator, the Australian Aged Care Quality Agency, saw the footage of Mrs Robins' treatment, it sanctioned Morrison Lodge and suspended Government funding for new residents for three months.

Since then, the home's 100 per cent accreditation rating has been restored and anyone looking at reports on the Quality Agency's website will find no mention of what happened there.

Four Corners has uncovered more disturbing cases of assault and untimely deaths at homes across Australia but despite this, those homes maintain their 100 per cent accreditation rating from the Quality Agency.

There are no references to cases of mistreatment or complaints on the Aged Care Quality Agency's website, leaving families and prospective residents in the dark when researching the quality of care offered by homes.

Mrs Robins, who is now 94, remains at Morrison Lodge and so does the video camera.

"I don't think many Australians know what goes on. There should be cameras in every room," Mr Robins said.

Watch Part Two of Who Cares? Four Corners' major investigation into aged care at 8.30pm on ABC TV and ABC iview.