Dominique Strauss-Kahn had a tarnished name but impeccable connections. Thierry Leyne had spent years as a low-profile deal maker who wanted to climb into the big leagues of global finance.

The two met just after Strauss-Kahn quit as head of the International Monetary Fund in May 2011 amid a scandal over sexual-assault charges, which were later dropped. They founded financial-services firm Leyne, Strauss-Kahn & Partners and set about raising $2 billion for a hedge fund.