The US Justice Department took a win and a loss this week in its prosecution of an alleged $2bn corruption scheme in Mozambique that destabilised the impoverished country’s economy.

On Monday, a former banker at Credit Suisse became the first person to plead guilty in the case brought earlier this year by federal prosecutors in New York and Washington, D.C. Less than 24 hours later, South Africa’s justice ministry rejected the Justice Department’s request to extradite another defendant in the case — Mozambique’s former finance minister, Manuel Chang, who was arrested in Johannesburg in December at the request of US authorities.