Elizabeth Hudson, who lived at Dingle Meadow in Oldbury due to her living with dementia, died as a result of an attack from Michael Williams – who bosses now admit should not have been living at the home.
Mr Williams, from Birmingham, strangled and punched another resident around two weeks before the incident and had attacked a member of staff days after moving in.
He had also previously carried out a similar attack on 84-year-old Mrs Hudson to the one that killed her.
Staff increased observations but he was still able to pick Mrs Hudson, 84, up from her favourite chair and throw her onto the floor on March 16 last year.
Mrs Hudson had lived in the home since February 2013, with Mr Williams moving in in February 2016 after suffering a fall.
Mrs Hudson's son Peter, who lives in Pelsall, Walsall, said: "My mother had lived with dementia for a number of years but it reached a point where we decided it would be best to put her into care.
"When we went to look at Dingle Meadow we saw that my mother's brother was actually living there, he looked well and that made us feel positive about the care she would receive there.
"The staff were great there, they were very helpful and looked after my mother."
Coroner Zafar Siddique said that he was disappointed that communications between Sandwell Council social workers and the home had been so poor and he would be writing letters to each to ask that a more rigorous testing process is put in place before people are sent to homes.
He delivered a narrative verdict stating that Mrs Hudson had died as a result of a bleed to the brain and a fractured hip which came from the attack.
He said: "I am going to write a report because I do have concerns about the lack of communication regarding Mr Williams medical history."
West Midlands Police temporary detective chief inspector Colin Mattison said the force had been considering charging Mr Williams, who suffered from schizoaffective disorder and had to have monthly injections to try and contain his bipolar personality, with manslaughter but his death in December of last year put an end to that possibility.
He said: "Investigations after the event led to us discovering that Mr Williams had a history of violence.
"On top of that, there had been eight recorded incidents involving him since he moved to the home from hospital.
"However, a social worker who recommended he move to Dingle Meadow was not aware of his history, so in turn the home wasn't when he arrived.
"In my opinion, he should not have been there.
"We were looking at a number of different charges including manslaughter that he could potentially face when his death last December put an end to that."