Probably already covered but found a watchdog website/blog with tons of newsworthy criminal activity reporting, court documents, links, etc. This particular article provides the most information on this case to date. Perhaps this is why all those guys at the Pentagon, I think I read close to 5k employees ended up with illegal child-porn on their government computers?

http://vaticproject.blogspot.com/2016/10/lawyer-dark-web-child-porn-site-ran.html?m=1

“The FBI distributed child pornography to viewers and downloaders worldwide for nearly two weeks, until at least March 4, 2015, even working to improve the performance of the website beyond its original capability,” Peter Adolf, an assistant federal defender in the Western District of North Carolina, writes in a motion to have his client’s indictment thrown out."

“As a result, the number of visitors to Playpen while it was under Government control [increased] from an average of 11,000 weekly visitors to approximately 50,000 per week. During those two weeks, the website’s membership grew by over 30%, the number of unique weekly visitors to the site more than quadrupled, and approximately 200 videos, 9,000 images, and 13,000 links to child pornography were posted on the site,” he continues.

"Christopher Allen, a spokesperson for the FBI, declined to comment on matters pending litigation."