Mexican prosecutors have called officials at national oil company Petroleos Mexicano (Pemex) to give testimony in the “car wash” bribery and corruption scandal that has engulfed Brazilian engineering company Odebrecht and petrochemicals producer Braskem.

As a consequence, Pemex has published details of four contracts it signed with Odebrecht between 2010 and 2015. It said the move is part of the company’s commitment to transparency and follows an order from the attorney general’s office to cooperate with investigators.

The contracts include one signed in February 2010 with Braskem and Grupo Idesa to supply ethanol for the Ethylene XXI complex in Coatzacoalcos, Veracruz, two signed in February 2014 and November 2015 for construction of the Miguel Hidalgo Tula I and Tula II refineries respectively and one signed in November 2014 to upgrade the Salamanca refinery.

Pemex said in February it was probing allegations that Odebrecht paid $10.5 million in bribes to Mexican officials including $6 million to a high-ranking official at a state-controlled company. In December 2016, Odebrecht and Braskem pleaded guilty to charges brought by the US Department of Justice and agreed to pay a combined fine of at least $3.5 billion, the largest ever penalty in a foreign bribery case.

According to the US court ruling, Odebrecht paid approximately $788 million in bribes in association with 100 projects in 12 countries, including Brazil, Argentina, Colombia, Mexico and Venezuela between 2001 and 2016. In Mexico, Odebrecht paid $10.5 million to obtain public works contracts between 2010 and 2014, which generated more than $39 million in profits.