Residents at a Leicester care home for people with dementia and mental illness were "badly failed", a serious case review has found.
The report commissioned by Leicester City Council found patients were subjected to physical and sexual abuse from fellow residents.
Summer Vale Care Centre in Mowmacre Hill closed in October 2009 after a whistle-blower alerted the authorities.
A police probe uncovered 65 "sexual or concerning" incidents at the home.
The force said just seven incidents had been reported to them prior to their 2009 investigation, three of which had sexual connotations.
Police said the case was discussed with the Crown Prosecution Service last year but it was decided there was insufficient evidence to pursue a prosecution against Minster Care Management, which ran the home.
An allegation against a senior member of staff at Summer Vale Care Centre was still under investigation, police confirmed.
The male staff member is alleged to have pushed a male resident to the floor, causing him to be incontinent and suffer bruising.
Following its closure, a serious case review was commissioned by the city council's strategic director of adults and communities.
Dr Margaret Flynn, the report's author, said: "The serious case review found Summer Vale Care Centre did not ensure the safety of its residents.
"Although the exact number of abusive incidents in the home is unknown, a dismal picture of the lives of residents has emerged."
Dr Flynn said one female resident, whose care at the home was funded by the NHS, was "repeatedly physically and sexually assaulted" by male residents.
"There were lots of incidents and concerns and even though there were around 60 professionals involved in making sense of this information, all of whom agreed that something should be done, no-one asked searching questions and no-one assumed the lead role", she added.
A Care Quality Commission's inspection report, completed in March 2009, gave the home a zero out of five stars rating and described its performance as "poor".
The centre was home to 26 people, aged over 55 and suffering from dementia or mental illness.
Dr David Jones, chairman of the Leicester Safeguarding Adults Board, said: "This review paints a distressing picture of the day-to-day lives of a group of extremely vulnerable people.
"These are people who deserved - and had a right to expect - the very highest standards of care from the home which they and their relatives chose and trusted to care for them.
"It is very clear to everyone involved with this review that all agencies badly failed the residents of Summer Vale Care Home and their families.
"An action plan, which sets out the changes that need to be made by Minster Care and all of the agencies concerned, is in place and being acted upon."
A spokesman for Minster Care Group, which has 26 care homes across the country, said: "The safety and welfare of those in our care is of the utmost importance.
"It is regrettable that the quality of care at Summer Vale Care Centre did not meet the high standards expected by ourselves and the local authority partners, and deserved by our residents."
The spokesman said a £3.5m programme of investment was currently under way at the home, adding: "Staff at the new facility will be trained to the highest industry standards and residents will be fully assessed to ensure their needs are compatible with the level of care provision able to be delivered with the new facility."
The new care home is expected to be opened later this year.