CQC inspectors found care had deteriorated and the service breached five legal regulations relating to safe care, safeguarding, the physical environment, management and treating people with respect.
The home has been given the lowest possible rating of inadequate for being safe and well-led, down from requires improvement.
Ratings for being effective, caring and responsive have also dropped, from good to requires improvement.
The CQC said it would now closely monitor the home to ensure residents’ safety while improvements were made.
Regulatory action is also being taken to address concerns, which the home has the right to appeal.
The resident’s death was not examined as part of the inspection in May, the CQC said, as it was subject to further inquiries.