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.
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"People must be aware at all times that there are wild animals around them and they must make sure that their tents are properly closed."