The U.S. government has accused two former Twitter employees of spying on behalf of the kingdom of Saudi Arabia via their access to sensitive Twitter user data.

The case is the first of its kind pertaining to Saudi spying on U.S. soil, and it involves a U.S. citizen who was paid for his services by the kingdom, and a Saudi national who was employed by Twitter as a site reliability engineer from 2013 to late 2015 — as well as a Saudi national who worked as an intermediary between the Twitter employees and the kingdom.

As the Washington Post reports, the Twitter surveillance activities began in earnest in late 2014, shorly before now Crown Prince Mohammed bin Salmon (MBS) was named deputy crown prince following the January 2015 death of King Abdullah. The activities all appear directed by MBS, and as Brookings Institution senior fellow Tamara Cofman Wittes tells the Post, this case highlights "just how early" MBS began pursuing any and all critics — and it shows "a willingness to pursue these people even when it involves the subversion of major American corporations and the targeting of people in friendly countries."

Human Rights Watch researcher Adam Coogle, who just this week published a study of the Saudis pursuit of dissidents, calls the case "incredibly significant," and says it shows just how important Twitter has become in the kingdom, and how MBS acknowledged that. "Twitter is the de facto public space of Saudi Arabia," Coogle says, "the place where Saudi citizens come and discuss issues."

U.S. citizen Ahmad Abouammo was arrested this week in Seattle after being questioned by U.S. authorities last year. Abouammo, who worked at Twitter between mid-2014 and May 2015 as a media partnerships manager, allegedly met with a close associate of MBS, Bader Al Asaker, in London in November 2014, and almost immediately began looking up personal data on particular Twitter users. (The kingdom's intermediary, Ahmed Almutairi, is also charged in the case, and would later manage contact with Abouammo.) Abouammo is believed to have been paid $300,000 for his services, after which he departed Twitter and moved to Seattle in May 2015.

One of the dissidents targeted, referred to in the federal suit as "Twitter User 1," is believed to be Omar Abdulaziz, later a close friend of murdered journalist Jamal Khashoggi. Ahmad Abouammo and the other accused former Twitter employee, Ali Alzabarah, looked up data on Abdulaziz including IP addresses that showed his real-time location.

Alzabarah is a Saudi national who fled to Saudi Arabia the day after he was questioned by Twitter about his activities and placed on leave in December 2015. Alzabarah is accused of accessing over 6,000 accounts in his role as site reliability engineer, and when questioned about it, he reportedly said he was looking at the data "out of curiosity."

The case is a chilling reminder of how sensitive social media data can be used for evil and authoritarian ends. And the irony is not lost on us that the U.S. government was just recently advertising for a contractor to harvest Twitter data to identify possible shooters and terrorists.

As ABC 7 reports, Twitter issued a statement Wednesday saying:

We would like to thank the FBI and the U.S. Department of Justice for their support with this investigation. We recognize the lengths bad actors will go to try and undermine our service. Our company limits access to sensitive account information to a limited group of trained and vetted employees. We understand the incredible risks faced by many who use Twitter to share their perspectives with the world and to hold those in power accountable. We have tools in place to protect their privacy and their ability to do their vital work. We're committed to protecting those who use our service to advocate for equality, individual freedoms, and human rights.

Related: FBI Seeks Contractor To Harvest Facebook and Twitter Data To Identify Potential Shooters, Terrorists