Royal Dutch Shell and Italian oil major Eni bribed a known money launderer in Nigeria to secure a $1.1 billion joint exploration deal off the country’s coast in 2011, newly published documents reveal.

Emails released by the watchdog groups Global Witness and Finance Uncovered show that top executives at Shell and Eni knew the money they paid for oil block OPL 245 would go to former Nigerian oil minister Dan Etete. Etete, a convicted money launderer, then likely dispersed the payments to other government officials, including former Nigerian President Goodluck Jonathan.

“This is one of the worst corruption scandals the oil industry has ever seen,” said Simon Taylor, co-founder of Global Witness, in a statement. “Today’s new evidence shows senior executives at the world’s fifth-biggest company knowingly entered into a corrupt deal that deprived the Nigerian people of $1.1 billion.”

“To put that in context, the payment for this deal is worth more than Nigeria’s entire health budget for 2016,” Taylor added.

The emails, seen by The Huffington Post, show Shell representatives negotiating a price with Etete for the offshore oil field.

“Etete can smell the money,” Guy Colegate, a former MI6 agent who helped negotiate the deal, wrote in an email dated March 9, 2010. “If, at 70 years old, he does turn his nose up at 1.2 bill he is completely certifiable and we should then probably just hold out until nature takes its course with him.”

Shell’s then-CEO, Peter Voser, received that email after it was forwarded to him, the documents show.

Shell and Eni denied any wrongdoing.

To put that in context, the payment for this deal is worth more than Nigeria’s entire health budget for 2016. Simon Taylor, Global Witnes

“Neither Eni nor Shell paid any monies other than as contemplated and recorded by the Block Resolution Agreement and did not pay to [Etete’s Malabu Oil & Gas Ltd.], to Chief Dan Etete or to any public officer,” an Eni spokesman said in a statement to Reuters.

In a separate statement, Shell said, “it is Shell’s position that none of those payments were made with its knowledge, authorization or on its behalf.”

The two watchdog groups’ investigation coincided with similar findings that BuzzFeed News and the Italian newspaper Il Sole 24 Ore released on Sunday. Those reports said the amount of money involved in the bribery scheme was slightly higher, at $1.3 billion.

The findings come one month after U.S. President Donald Trump moved to repeal rules forcing oil companies to disclose payments to foreign governments to secure oil or mining deals.

The repeal of the so-called Cardin-Lugar rule ― created under the Dodd-Frank Act as part of the sweeping financial reforms enacted to prevent another Great Recession ― was the first bill Trump signed into law. Oil companies and interest groups claimed the regulation made U.S. oil majors, such as Exxon Mobil Corp., less competitive with foreign rivals.

Corruption is well-documented in the global oil industry. Last year, HuffPost and Australia’s Fairfax Media published a monthslong investigation into Unaoil, a secretive Monaco-based firm registered in the British Virgin Islands.

The company and its subcontractors paid out boatloads of money to foreign officials to win contracts, according to tens of thousands of internal documents leaked to HuffPost and Fairfax. The investigation dubbed Unaoil “the company that bribed the world.”

It’s now clear, however, that Unaoil wasn’t the only one.