Funds managed by KKR & Co LP (NYSE:KKR) will buy clinical research group PRA International from Genstar Capital LLC for an undisclosed amount, PRA said on Monday, underscoring growing private equity interest in the contract research industry. Sources familiar with the matter had previously told Reuters that PRA could be worth as much as $1.3 billion. The deal comes at a time when research service firms are either being snapped up by private equity firms or are being taken public. Genstar bought PRA in 2007 for $797 million and put it on the block earlier this year after failing to sell it in 2011. Warburg Pincus LLC and Cinven Ltd were also in the running to buy the company, the sources had said. PRA says it provides clinical trial services and other research for pharmaceutical companies in more than 80 countries to help them win regulatory approval for drugs.