Edits made to the Hillsborough disaster page on Wikipedia have been described as an "absolute insult to victims and their families".
Margaret Aspinall, mother of one of the victims said: "It's an absolute insult to the families who are fighting for where we are today and it has to be investigated".
Sheila Coleman from the Hillsborough Justice Campaign added that the distress was compounded by the timing of the revelations.
"That this happens now when the families are immersed in the inquest procedure goes to the heart of why should they trust the establishment," she said.
More top news
14-year-old Jasmine Elcock is the fourth Britain's Got Talent 'golden buzzer' act after leaving Ant in tears with her performance.
A band of heavy rain is heading for the UK, threatening to make the May Bank Holiday a washout, the Met Office has warned.
Headteachers could strike in protest at government plans to force schools to become academies