More details are emerging about the international law enforcement operation that dismantled Darkode, described by authorities as the world's biggest English-language online crime forum. Among the 70 people arrested worldwide are the site's alleged administrator, aged 27, and a 20-year-old man who allegedly designed malware intended to remotely control and steal data from Google Android devices.

The site had from 250 to 300 active members. Before it was shut down Tuesday, it had been secretly infiltrated by FBI agents for more than 18 months. While monitoring the day-to-day activities of members, agents observed advertised products including personal information of 39,000 people taken from a database of Social Security numbers, 20 million e-mail addresses and user names used in a variety of scams, ransomware programs, and other online criminal wares. Some of the users allegedly took part in hacks late last year on Sony's PlayStation and Microsoft's Xbox networks.

"Of the roughly 800 criminal Internet forums worldwide, Darkode represented one of the gravest threats to the integrity of data on computers in the United States and around the world and was the most sophisticated English-speaking forum for criminal computer hackers in the world," US Attorney Hickton of the Western District of Pennsylvania said in a statement published Wednesday morning. "Through this operation, we have dismantled a cyber hornets' nest of criminal hackers which was believed by many, including the hackers themselves, to be impenetrable."

Operation Shrouded Horizon, as the enforcement action was dubbed, was coordinated among the FBI and its counterparts in 19 other countries, including the UK, Denmark, Finland, Germany, and Israel. It's the biggest coordinated international law enforcement action ever directed at an online criminal forum. Like many such forums, Darkode was password-protected and required prospective members to be sponsored by an existing member and then vetted before being accepted. Candidates were required to submit a résumé of past criminal activity, notable hacking skills, and potential contributions to the forum. Active members would then decide whether to approve the applicant.

Word of the Darkode dismantling began spreading Tuesday when publications in Brazil reported arrests made in that country. The enforcement action was formally unveiled by US prosecutors Wednesday morning in Pittsburgh, Pennsylvania.