The late founder of L'Arche International, Jean Vanier, sexually abused six women, an investigation has concluded.
The investigation, carried out by independent consultancy GCPS, said that the women were non-disabled who, despite not knowing each other prior to the inquiry, shared similar accounts.
The women allege that Vanier initiated sexual relations, generally within the context of spiritual guidance, and that these relationships were manipulative and emotionally abusive.
The report said that the abuse spanned from 1970 to 2005.
"It is alleged that Jean Vanier, like Father Thomas Philippe, abused his power and used spiritual or mystical explanations in the context of spiritual accompaniment to justify his actions, and that he held a psychological hold on these women, many of whom have suffered in silence for many years," the report said.
"Jean Vanier asked each of the women to keep the nature of these events secret. These six women had no prior knowledge of each other's experiences, but they reported similar facts associated with highly unusual mystical explanations used to justify these behaviours."
Vanier, a Canadian and devout Catholic, died last year in Paris aged 90. He founded L'Arche in 1964 to provide a supportive environment for people with disabilities. Today the global network spans 38 countries.
The inquiry had sought to investigate the "early history" of L'Arche and founder Vanier, as well as his historical links to abuser Father Thomas Philippe, who is understood to have been his spiritual mentor.
Of Philippe, who died in 1993, the report noted a 2015 canonical investigation which concluded that he had sexually abused non-disabled adult women through whom he claimed to seek and communicate a mystical experience. Vanier denied all knowledge of these abuses.
It added that there was "nothing in the investigation to suggest that Jean Vanier harmed people with disabilities".
Stephan Posner and Stacy Cates Carney, leaders of L'Arche International, wrote in a letter to the L'Arche Federation: "We are shocked by these discoveries and unreservedly condemn these actions, which are in total contradiction with the values Jean Vanier claimed and are incompatible with the basic rules of respect and integrity of persons, and contrary to the fundamental principles on which L'Arche is based.
"We recognise the courage and suffering of these women, and of any others who may not have spoken up...
"We ask forgiveness for these events which took place in the context of L'Arche, some of which were caused by our founder."
Loren Treisman, CEO of L'Arche in the UK said the revelations were "extremely upsetting".
"L'Arche in the UK is thoroughly shocked and saddened by this news. Jean Vanier was an admired figure and the findings of this report will cause pain for many," she said.
"We unreservedly condemn Jean Vanier's actions. They are in total contradiction to the values that he claimed and are contrary to the fundamental principles of our organisation, which affirm the unique value in every person.
"We want to acknowledge and thank the victims for their courage and express our heartfelt regret for the trauma they had to endure. We are devastated that our founder abused his position of power and caused deep hurt to some of his victims."