Mum passed away. I have written about how terrible it was on here before. What I didn't say was prior to her becoming really sick....Advice?

Mum had told me on three separate occassions that a man had been on her room late at night stocking her in her gentiles. I had told the manager of the facility who answered is she saying it so she can leave. I told the Dr of the facility another time who said was she sexually abused as a child. It was a 3 story high building. I asked if there were security cameras I was told no. I was in shock and thought Mum might have been confused and half asleep ,she was on sleeping pills and lorazapam once a day for anxiety. She said it didn't hurt so I didn't ask for her to have an internal examination. I made arrangements to transfer her to another facility. But we went into covid lock down for 7 days. I phoned her as usual and she told me she had stood at the door pushing it closed each time it opened about 5 times. She told me she said to herself you won't get me tonight. After I moved her to the other facility her care was worse and she went to hospital, passed away from a twisted bowel. I did write about it here before. I read all my diaries I wrote in every day about Mum and as Mum spoke to me on the phone I put all the details together like a jigsaw when I read what she said. About a younger man came into her room with his friend to see her room. I remember meeting him, he was only about 70 and seemed very fit and healthy. I did wonder why he living in care. He had been very familiar with me, put his arm around my shoulders on 2 occassions when Mum and I had spoken to him and his friend . Mum had said he used to hold her chair out for her to sit on and the caregivers had always said none of that. Mum told me he had stopped talking to her or looking at her. It was not long after that she told me about a man who she couldn't see in the dark when she was half asleep coming into her room and rubbing up and down in her private area. Mum was never a sexual person and had lived without a man 8n her life for 60 years. She never spoke of sex and was always a lady. I was not allowed to swear growing up I was Mum's only child. When Mum died reading my diaries I decided I would tell the police. Police said they phoned the facility manager and were surprised there were no cameras in new aged care facility. They said that because my Mother has passed away they have nowhere to start the investigation. I asked about the other elderly ladies there who may be at risk. Unfortunately there is nothing they can do. I am sick, thinking I didn't believe my Mum, I was in shock and took direction from the Manager and the Drs reactions. But I know my Mum didnt lie, when I go back through my writing and things Mum said. Mum had never been a problem to the staff but it was about 2 weeks before Mum told me for the first time about the abuse, the nurse emailed me said Mum had been found not wearing underpants in the early hours of the morning had been upset when the staff tried to put pants on her. Another time early morning she had been throwing items on the floor when the staff came in early morning and wouldn't let them near her. Not long after Mum told me about the abuse. I am ashamed I didn't take her home with me then. She held my hand said please don't leave me here I am begging you. We both crying I called nurse and left. I drove home in shock as was first time she told me about the sexual abuse other times was on the phone then went into lock down. It would be easy to say Mum had dementia.. Dr put dementia on Mum's medical form when she moved to the next facility. Mum had never been categorized as dementia before the sexual abuse claim. Mum had depression and anxiety. Her depression was worse she didn't want to be in the care facility. she only gave up her home agreed to go into care because she would be closer to me I had moved a long way from her. I promised she live with me if not happy but I let her down changed my mind couldn't cope with the stress. Is the response re sex abuse from all authorities acceptable? I need your advice and thoughts.