Patients died due to poor care at a home at the centre of the UK's biggest inquiry into alleged neglect, a panel has found.
The Nursing and Midwifery Council (NMC) panel said the failings of five nurses at Brithdir Care Home, near Bargoed, amounted to misconduct.
Tembakazi Moyana, Rachel Tanta, Daphne Richards, Susan Greening and Beverley Mock may face sanctions.
The failings were investigated by Operation Jasmine.
In May, a disciplinary panel found 86 failings proved out of an alleged 150 against six nurses in relation to nine residents between 2004 and 2006.
On Friday, the NMC disciplinary panel told a hearing in Cardiff those connected to one nurse, Rachel Pritchard, did not amount to misconduct but those against the others did.
These related to poor management of patients' pressure sores, record keeping at the home and other deficient care, the panel said.
In one instance, a resident was admitted to hospital with 16 pressure sores, which one expert described as "astounding".
Miss Moyana was said to have fundamentally breached the relationship between nurse and patient with deficiencies in care being directly responsible for causing the deaths of two patients.
The panel referred to her "underlying callous, deep-seated attitude".
Ms Tanta, the panel found, had shown a lack of concern for patients and a lack of respect for human dignity with her "couldn't-care-less attitude".
Ms Richards failed to have a resident seen by a GP until she was pressured to do so by an inspector, with her actions causing pressure sores on one patient, the panel said.
The panel found Ms Greening, who had been promoted to manager for four months, put patients at risk by failing to train staff properly, while Ms Mock was said to have exposed patients to an unwarranted risk of harm.
In many of these cases, the patients were elderly and highly vulnerable, the panel said.
Any sanctions the five nurses face will be decided at a further hearing on 17 August.
Last year, an NMC panel found seven misconduct charges proved against Christine Hayes, the director of nursing at the Caerphilly Local Health Board between 2003 and 2006.
She was found to have kept moving people to the home despite knowing of serious concerns over standards, and was struck off in January this year.
Concerns were raised about Mrs Hayes' actions during Operation Jasmine - an investigation by Gwent Police into allegations of neglect in south Wales care homes.
The £11.6m police inquiry collapsed when the former owner of the Brithdir home, Dr Prana Das, was declared unfit to stand trial as a result of a brain injury suffered in a violent burglary.
The home - which has 40 residents with dementia, mental infirmity and learning difficulties - is now under new management.