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. The bank wasn’t accused of wrongdoing and cooperated with the government investigationsBerko 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. 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. “Is anyone going to testify to having seen a bribe or being paid a bribe?