A former Goldman Sachs Group Inc banker went on trial Tuesday for allegedly bribing government officials in Ghana to secure a lucrative power plant deal for a client.

Asante Berko, 52, and his associates outside the bank paid high-ranking government officials in the West African nation more than US$1 million in bribes a decade ago to approve the development and financing of the multimillion-dollar power plant, prosecutor Katherine Raut told a federal jury in Brooklyn, New York in her opening statement.

Berko hid the alleged scheme from Goldman’s compliance department, according to the US. The bank wasn’t accused of wrongdoing and cooperated with the government investigations

Berko was a member of the team at Goldman responsible for securing and managing financing for the power plant project. Prosecutors allege the bribes were paid to obtain the necessary approvals for a Turkish company, in which Goldman held a 16% stake, and that Berko laundered the bribe money through US financial institutions.

Raut told the jury so many “red flags” were eventually raised by Goldman Sachs that it pulled out of the project. She promised jurors that during the two-week trial, they would see a trove of evidence — including bank records and emails — outlining the bribe scheme. 

In one email, Berko directed accomplices to “keep our conversations to private email,” and in another 2015 message, an associate of Berko told him an official in Ghana was “waiting for the ‘holy rain’ and would appreciate it sooner rather than later,” according to the prosecutor. The US has said the messages and others are proof of illicit payoffs.

Berko has pleaded not guilty and his lawyer, Robert Boone, told jurors the government’s evidence would fail to show his client’s role in any bribery scheme. Boone compared the government’s case to the pop group Milli Vanilli, which was exposed for lip syncing and not actually singing on their recordings.

“Where are the witnesses to Mr Berko’s bribery?” he asked. “Is anyone going to testify to having seen a bribe or being paid a bribe? The answer is no.” 

Berko is accused with violating the Foreign Corrupt Practices Act, or FCPA, conspiracy and engaging in a money-laundering scheme. He faces as long as 20 years in prison if convicted on the most serious charge against him.