US authorities are investigating whether Och-Ziff Capital Management knew that part of a $150 million investment in a small African miner would wind up in the hands of Zimbabwe President Robert Mugabe’s government, according to people familiar with the probe.

Och-Ziff last year disclosed that a broader Justice Department and Securities and Exchange Commission investigation is examining the $47 billion New York hedge fund's business in Africa under the Foreign Corrupt Practices Act. The act bars firms doing business in the US from giving money or items of value to foreign officials for business, either directly or through intermediaries.