A care worker slapped and swore at vulnerable and elderly residents, a court has heard.
Carer Emma Morse and the home's manager and a company director all neglected residents at the home in Penzance, Truro Crown Court heard.
Mrs Morse denies six counts of ill treatment of people who lack capacity.
Manager Robert Rogers and human resources director Anna Dalziel deny neglecting residents by not acting upon the allegations of abuse.
Mrs Morse allegedly abused four "vulnerable and elderly" residents between December 2011 and January 2013.
The residents, aged between 85 and 90, were placed by Cornwall Council and have all since died.
At the trial's opening Jonathan Barnes, for the prosecution, told the jury Morse, 50, of The Close, Penzance, became agitated and hit out at resident George Baker, 85.
He said Mrs Morse slapped Mr Baker "hard on his back" and swore at him.
Mr Barnes said Mrs Morse "grabbed the wrists" of Mavis Pearce, 90, who had dementia, and "shouted in her face and shook her".
The prosecution said two members of staff complained to manager Mr Rogers, 44, of Tremore Road, Redruth in September 2012.
He exchanged emails with Swallowcourt's human resources director Miss Dalziel, 36, of Redannick Lane, Truro.
But neither Mr Roberts nor Miss Dalziel notified the Care Quality Commission or the local safeguarding organisation as required by law and no action was taken against Mrs Morse.
The prosecution claim Mrs Morse then went on to abuse other residents including Dennis Drew, an 86-year-old with cerebral palsy.
Mr Roberts denies two counts of ill treatment or neglect of people who lack capacity, and Miss Dalziel denies one count of the same charge.
The trial continues.