A spokesman from Shaw Healthcare on behalf of the home said the allegation was being taken "extremely seriously".
Members of staff connected to the incident have since been suspended, pending the outcome of a police and our own investigation.
We acknowledge the anxiety and distress that this has caused the resident and their family and we also wanted to have the opportunity to reassure the other residents and families so have held meetings to update them on the situation and let them know that we are taking the matter extremely seriously."
A previous CQC inspection of The Granary highlighted some areas for improvement, but the care home owners say it is "unrelated to the current situation."
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A photographic exhibition celebrating the people that keep Bristol running overnight has opened at the Harbourside Arts Centre.
It's another mild and grey day with some rain around Gloucestershire and Bristol.
It's looking cloudy and grey into tomorrow morning with some heavier rain in Gloucestershire and Bristol.