Boosting its efforts to expose dealers of conflict diamonds, the United Nations may enlist private investigators to “name and shame” dealers who buy stones from Angola’s UNITA rebels. The U.N. Security Council plans to hire Kroll Associates, a New York-based investigative firm, to trace cash used by the rebels.

A recent U.N. report on the Angolan diamond situation argued that throwing the spotlight on the illicit trade is the only way to end it. But the report noted that transactions in the diamond world are hard to trace, since parcels can be mixed up, and diamonds often acquire false documentation.

Previous U.N. reports suggested that major De Beers sightholders still knowingly buy stones from UNITA over the border in the Democratic Republic of Congo. De Beers has called these reports false.

Kroll will receive a fee of $75,000 plus expenses for the 16-week probe, Reuters news service reported. A Kroll spokeswoman says the company “is honored that the U.N. is entrusting the firm with this assignment” but declined further comment, except to stress that the deal is not yet final.