https://arstechnica.com/tech-policy/2017/03/doj-drops-case-against-child-porn-suspect-rather-than-disclose-fbi-hack/

DOJ: "Disclosure is not currently an option."

"The government must now choose between disclosure of classified information and dismissal of its indictment," Annette Hayes, a federal prosecutor, wrote in a court filing on Friday. "Disclosure is not currently an option. Dismissal without prejudice leaves open the possibility that the government could bring new charges should there come a time within the statute of limitations when and the government be in a position to provide the requested discovery."

The Department of Justice is currently prosecuting over 135 people nationwide whom they believe accessed the illegal website. However, in order to find those people, federal authorities seized and operated the site for 13 days before closing it down. During that period, the FBI deployed a Tor exploit that allowed them to find out those users’ real IP addresses. The use of Tor, which obscures and anonymizes IP addresses and browser user agents, makes it significantly more difficult for individuals to be tracked online. With the exploit, it became extremely easy for suspects to be identified and located.

Defense attorneys have attempted to gain access to some, if not all, of the NIT’s source code as part of the criminal discovery process. In a related case prosecuted in New York, an FBI search warrant affidavit described both the types of child pornography available to Playpen’s 150,000 members and the NIT’s capabilities.

Another one of those ongoing Playpen-related cases is United States v. Tippens, which is also being prosecuted in the same federal court in Tacoma, and is being heard by the same judge. The defendant there, David Tippens, is being represented by the same federal public defender, Colin Fieman. Despite all those parallels, Judge Bryan denied the defense's request to suppress evidence in Tippens—the case is set to go forward as a bench trial (without a jury) later this month.

Last year, Christopher Soghoian, a security and privacy expert formerly with the American Civil Liberties Union, spoke before the annual Chaos Communication Congress about Michaud and related cases. Soghoian wasn’t just acting as a pundit: he served as an expert witness during earlier hearings in Michaud. Soghoian, who is currently serving as a technology fellow in Congress, has often raised many concerns about such surveillance.

"My concern with the economics of hacking is that if the government hacks enough people, hacking not only becomes an attractive way of surveilling but it becomes the cheapest way to spy on people," he said in December 2016.