A mother fighting for seven years to find out why her 20-year-old son died by hanging at a mental health unit has called for a public inquiry.
Matthew Leahy was detained under the Mental Health Act at the Linden Centre in Chelmsford, Essex. Eight days later he was found unresponsive in his room.
The health ombudsman uncovered 19 instances of serious failings.
Essex Partnership University NHS Trust said care provided by a former trust "fell below acceptable standards".
It apologised for the "additional pain and distress" caused by North Essex Partnership's "inadequate" investigation into Mr Leahy's care and death.
Melanie Leahy said her son "should have been in a place of safety" when he was taken to the Linden Centre with a diagnosis of delusional disorder in November 2012.
The ombudsman found, among other failures, that he did not have a nurse in charge, his physical health was neglected and there was a failure of observation at a critical time.
Allegation of rape
"My life has changed for evermore, I've been at it seven years - I can't leave it alone," said Ms Leahy.
"There have been 20 investigations, nine reports, three reviews but I know I still haven't had all the answers as far as Matthew is concerned."
A recording of a 999 call made by Mr Leahy has just been released, along with a full report by the Parliamentary and Health Service Ombudsman (PHSO), some of the details of which were published in June.
In the call, Mr Leahy alleges he was raped at the unit "but doctors refuse to acknowledge it".
Staff actions 'disgraceful'
Essex Police investigated and no arrests were made but the ombudsman, which followed up Ms Leahy's complaints, found the mental health trust failed to follow its own rape allegation procedures.
"What we discovered as a result of our investigation were serious failures and maladministration in 19 instances in his care," said Rob Behrens, the Parliamentary and Health Service Ombudsman.
"After Matthew died, members of staff went to the care plan and changed it to make it look as though a care plan was in place before he died.
"That is disgraceful."
'Not just for Matthew'
Ms Leahy has gathered more than 100,000 signatures to get her son's death raised in Parliament.
"If we can get this to a debate then I think anyone who has lost a loved one within the mental health system in this country will have a voice.
"It's not just for Matthew, but for every single one of those boys and girls, every single one of you that's been failed."
NHS Improvement is due to announce its lead for a national review into "significant failings" at North Essex Partnership, dating back more than a decade.
The Health and Safety Executive is conducting a separate investigation into how the trust managed wards in relation to ligature points between 2004 and 2015.