Russian hacker Yevgeniy Nikulin found guilty for LinkedIn, Dropbox, and Formspring data breach back in 2012 and the sale of their users data on cybercrime black marketplaces. Russian criminal was arrested in Prague in October 2016 in an international joint operation with the FBI. Nikulin used data stolen from Linkedin to launch spear-phishing attacks against employees at other companies, including Dropbox. The data stolen by Nikulin were available on the cybercrime underground between 2015 and 2016, they were offered for sale by multiple traders.”]
Source: https://securityaffairs.co/wordpress/105790/cyber-crime/nikulin-hacker-found-guilty.html