After oil field development began during the Second Sudanese Civil War, Block 5A was the scene of extensive fighting as rival militias struggled for control.

[12] After hostilities resumed, the Sudan People's Liberation Movement/Army (SPLM/A) captured Leer from the government in March 1986, and the town became a stronghold of the rebel commander Riek Machar, who had been born there.

[16] Riek was made commander in chief of the South Sudan Defense Force (SSDF), which included most of the ex-rebels who had signed the Khartoum agreement.

[16] The swampy and inaccessible region had no strategic value to the Khartoum government before the approach of the pipeline that was built from Port Sudan on the Red Sea to Heglig, not far to the north.

[18] In 1998–1999, Paulino's fighters and government troops clashed several times with Riek's forces in a struggle for control of the Unity state oilfields.

[23] On 11 April 2011 Gatluak Gai's son-in-law, Major General Peter Gadet, now of the "South Sudan Liberation Army", published the "Mayom Declaration".

[27] After the resumption of exploration and development, on 6 February 1997 the Sudanese Government granted the block 5A concession to a consortium of Lundin Oil of Sweden, OMV of Austria, Petronas of Malaysia and Sudapet of Sudan.

[32] In 1998 the consortium established a drilling site at Ryer, in Jagei Nuer territory, near the port of Thar Jath on the Nile.

[33] The first exploration well at the Thar Jath field was spudded on 7 April 1999, expected to reach the Cretaceous Bentiu and Darfur sandstones at a depth of around 3,200 metres (10,500 ft) in four to six weeks.

[34] According to a Lundin report: "... in view of increasing instability in the area, to ensure maximum security for its personnel and operations, the Consortium decided to suspend seismic and drilling activities on Block 5A as a precautionary measure".

[35] In March 2003, Lundin said there had been "positive developments in the peace process and the improved conditions in its concession area" and said that it was planning to undertake infrastructure work "as a first step towards an eventual recommencement of activities".

[36] In June 2003 Lundin Petroleum completed sale its working interest in Block 5A to Petronas Carigali for USD 142.5 million.

[10] In 2006 White Nile (5B) Petroleum Operating Co started production at the Thar Jath field in Block 5A on behalf of the Contractors (Petronas, ONGC and Sudapet).

[10] Unlike other oilfields in Sudan, there was no forcible displacement of the civilian population until about 1998, when the consortium led by Lundin Oil started exploration.

[38] At that time a government-supported Nuer militia under Major General Paulino Matiep began attacking communities in Block 5A, including Leer.

[43] In June, July and August Paulino Matiep's forces attacked Leer, looting and destroying houses and buildings such as the hospital, NGO compounds and churches.

They've been forced to hide for days in the surrounding swamps and outlying villages, living in constant fear and surviving on just water lilies [a wild food] and fish.

[45] The United Nations Office for the Coordination of Humanitarian Affairs defined Unity State as being an area of acute emergency, the worst possible classification.

[47] A study of Landsat data between 1999 and 2004 showed major shifts in land use that closely corresponded to reports of fighting in the block.

Between 1999 and 2002 most farming activity stopped in the bands that extended 10 kilometres (6.2 mi) on each side of the newly built oil roads.

[49] A report published by the International Crisis Group on 10 February 2003 described a renewed push to clear the road south from Bentiu to the port of Adok on the Nile.

It said "The offensive from late December until the beginning of February was an extension of the government’s long-time strategy of depopulating oilrich areas through indiscriminate attacks on civilians in order to clear the way for further development of infrastructure.

Eyewitness accounts confirm that the tactics included the abduction of women and children, gang rapes, ground assaults supported by helicopter gunships, destruction of humanitarian relief sites, and burning of villages.

[50] Examination of Landsat images in 2006 showed that the all-weather roads built to access the oil fields have disrupted the drainage patterns of the marshes.

[52] In November 2009 the German NGO Sign of Hope reported that in the village of Rier, close to the Thar Jath Central Processing Facility, there were critical levels of salts and contaminants such as cyanides, lead, nickel, cadmium and arsenic.

The investigation was triggered by an 8 June 2010 report published by the European Coalition on Oil in the Sudan, an NGO based in the Netherlands.

[58] The report claims that Lundin's decision to explore and then extract oil from Block 5A started the war for control of the area.

[2] The investigation is sensitive because Carl Bildt, Swedish Foreign Minister, was a board member during the years when the alleged abuse occurred.