Teams of lawyers from Gibson Dunn & Crutcher, Tooks Chambers and City litigation firm Saunders Law are working pro bono for the families of the Hillsborough disaster as those affected by the tragedy continue their campaign for justice.

The Hillsborough Families Support Group this weekend confirmed that it is seeking a fresh inquest into the events that led to the deaths of 96 football fans in 1989, and hinted at criminal prosecutions against individuals involved, saying "those responsible can avoid accountability no longer".

The lawyers working on the case are currently searching through almost half a million pages of newly disclosed evidence, with a team from Tooks Chambers led by Michael Mansfield QC alongside Hugh Southey QC and barristers Adam Straw and Patrick Roche putting together the case for a new inquest. Due to the high volume of work involved, it is expected that the size of this team will soon be doubled.

Prime Minister David Cameron last week indicated that attorney general Dominic Grieve will be studying the new evidence before deciding whether or not to launch a new inquest, which could quash the original inquest's verdict of accidental death.

"I shouldn't see why it should take the attorney general any longer than four to six weeks to make a decision – it's not rocket science, as the panel has done all the work for him," said Mansfield.

He added: "The Director of Public Prosecutions will need to look at the conspiracy as there was an attempted cover-up and a smear campaign against the victims. Civil actions may also need to be revisited as they were based on false information."

Former Lord Chancellor, Charles Falconer (pictured), a partner at US firm Gibson Dunn, is leading a team from his firm considering the civil implications of the evidence. The team includes London associates Daniel Barnett, Doug Watson and Christopher Loudon.

In addition, a team from Saunders Law led by managing director James Saunders is looking at potential criminal prosecutions. The London firm has previously worked on high-profile cases such as the murder appeal of Norfolk farmer Tony Martin.

The Hillsborough report released last week, which was compiled by an independent panel, revealed that the South Yorkshire Police – which was advised by Squire Sanders legacy UK firm Hammond Suddards – had altered over 100 statements of evidence.

The report identified Hammond Suddards partner Peter Metcalf as having worked with a small team of officers managed by SYP Chief Superintendent Donald Denton. Metcalf left the firm in April 2000 and subsequently retired from practice in 2002.