A care home has been put in special measures following an investigation into a "higher than expected number of deaths".
The Care Quality Commission (CQC) has published a report rating Sunningdale House in Perranporth, Cornwall as inadequate.
Last month Cornwall Council removed its residents and police started investigating safeguarding concerns.
The owners South West Care Homes said they "continue to work with the CQC".
The CQC carried out unannounced inspections in March and April after it was told of "serious concerns from health and social care professionals about the care that people received".
The concerns included end of life planning, personal care needs and a higher than expected number of deaths.
Inspectors found staff were inadequately trained with one commenting: "We learnt everything by doing things wrong, or not doing them at all and getting blasted for it."
The report said care staff had not received any training in safeguarding and had "limited or no knowledge about the safeguarding process and how to recognise potential signs of abuse or mistreatment".
It concluded the service was not safe, effective, responsive or well-led, and not always caring.
Nicky Nendick from the CQC said: "We found systemic failings in the oversight and the monitoring of care at Sunningdale House.
"This resulted in inadequate measures in place that did not provide the right care, staff training or medication checks in place and safety checks were not robust enough to ensure the quality of care delivered was monitored and improved."
South West Care Homes said in a statement: "Sunningdale House is being refurbished. Its registration will be reclassified as 'dormant'.
"We will continue to work with the CQC and the council to reassure them that Sunningdale House can provide the same high standards of care highlighted in previous inspections."
There are currently no residents at the home and it will be inspected again within six months.