The Cabinet Office said it believes "one or two" individuals are behind "sickening" amendments made to the Wikipedia page on the Hillsborough disaster from Government computers, but said it could be "challenging" to identify the culprits.
A Cabinet Office spokesman said:
The amendments made to Wikipedia are sickening. We are treating this matter with the utmost seriousness. Our first priority is to establish the facts and to examine the issues raised. Once we have the facts, we will update Parliament with the findings and consider further appropriate action.
At this time, we have no reason to suspect that the Hillsborough edits involve any particular department, nor more than one or two individuals in 2009 and 2012.
As the first incident happened five years ago and there are hundreds of thousands of people on the Government's network, it may prove challenging to identify who was involved. But we are exhausting every option.
More top news
As Obama signed off with his last major speech in office, ITV News asked his supporters what a difference he has made in eight years.
Lloyds Banking Group is cutting 3,000 jobs and shutting 200 branches as the lender braces for a cut in interest rates, it has announced.
EDF is set to make a final decision on the planned nuclear power station at Hinkley Point, ending doubts over the £18 billion project.