US anti-bribery investigators are targeting a former Halliburton subsidiary over its work on a key Royal Dutch Shell project in Nigeria, widening a corruption probe into the country’s troubled oil industry.

The US investigation into Halliburton’s Nigerian operations – which covers a period when it was headed by Dick Cheney, US vice-president – has uncovered evidence of bribery and is now looking at a range of payments made in a number of countries over the past 20 years, according to the company.