Amnesty International on Tuesday called on Nigeria, the UK and the Netherlands to launch investigations into Anglo-Dutch oil giant Shell, over its role in a swathe of horrific crimes committed by the Nigerian military government in the oil-producing Ogoniland region in the 1990s.

The organization has released a ground-breaking review of thousands of pages of internal company documents and witness statements, as well as Amnesty International’s own archive from the period.

In 1993, the Movement for the Survival of the Ogoni People declared that Shell was no longer welcome to operate in Ogoniland over its devastating impact on local soil and environment degradation caused by oil spills and gas flaring.

According to Amnesty International, MOSOP activists faced numerous human rights violations, including the unlawful killing of hundreds of Ogonis, as well as torture and other ill-treatment, including rape, and the destruction of homes and livelihoods.

The Nigerian military’s campaign to silence the Ogoni people’s protests against Shell’s pollution led to widespread and serious human rights violations, many of which also amounted to criminal offences.

“The evidence we have reviewed shows that Shell repeatedly encouraged the Nigerian military to deal with community protests, even when it knew the horrors this would lead to – unlawful killings, rape, torture, the burning of villages,” said Audrey Gaughran, Director of Global Issues at Amnesty International.

“In the midst of this brutal crackdown Shell even provided the military with material support, including transport, and in at least one instance paid a military commander notorious for human rights violations. That it has never answered for this is an outrage.

“It is indisputable that Shell played a key role in the devastating events in Ogoniland in the 1990s, but we now believe that there are grounds for a criminal investigation. Bringing the massive cache of evidence together was the first step in bringing Shell to justice. We will now be preparing a criminal file to submit to the relevant authorities, with a view to prosecution.”

According to the report based on company documents, strategy papers, internal memos and letters to officials, Shell stopped operations in Ogoniland in early 1993 citing security concerns, but subsequently sought ways to re-enter the region and end the MOSOP protests.

The authors of the report said that on several occasions Shell provided logistical assistance to Nigerian military or police personnel, specifically transport.

Shell has always denied that the company was somehow involved in the human rights violations and crimes that were carried out by the Nigerian government and armed forces in Ogoniland in the 1990s.