Instead, the social media company sent Richard Allan, its vice president of policy solutions, to answer questions at the unprecedented hearing by the worldwide "grand committee" held in the UK Houses of Parliament on Tuesday.
In Zuckerberg's place, Facebook sent Richard Allan, their vice president of policy solutions. After Zuckerberg repeatedly refused to attend questioning by that panel, the inquiry joined together with lawmakers from other countries to add weight to their calls for him to appear.
The committee turned up the heat by seizing confidential Facebook documents from the developer of a now-defunct bikini photo-searching app.
"An engineer at Facebook notified the company in October 2014 that entities with Russian IP addresses had been using a Pinterest API key to pull over three billion data points a day through the Ordered Friends API", said Collins.
Six4Three is suing Facebook and the emails cited by Collins have been sealed by a California court.
An worldwide parliamentary panel hearing comprising of members from nine countries got together today to grill Facebook for its inability to combat fake news and manipulation of facts on its platform.
Damian Collins, in charge of the hearing and committee, said in a Sunday tweet that he had reviewed the documents. According to internal company documents, a Facebook engineer warned the social media giant of a data issue involving Russian Federation in 2014 - earlier than Facebook has previously publicly admitted.
The lawmakers - which included representatives from Canada, Ireland, Brazil, Argentina, Singapore, Belgium, France, Latvia and Britain - were also critical of Facebook founder and chief executive Mark Zuckerberg for failing to show up to answer questions in Britain's parliament, and made a point of leaving an empty seat with Mr. Zuckerberg's name tag.
"We have to start looking at a method of holding you and your company to be accountable, because Mr. Zuckerberg, who is not here, doesn't appear to be willing to do the job himself", said Charlie Angus, a Canadian lawmaker.
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The report was the work of three hundred federal and non-federal scientists and experts from across a variety of federal agencies. Damaging weather alone, it says, has cost the USA almost $400 billion since 2015, and those costs are only expected to increase.
"I think it's important we have this king of engagement but I also have a role supporting my company as it tries to grapple with the issues that we're talking about today", Allen said.
Collins did, however, question Allan during the hearing about one email included in the document trove that was written by a Facebook engineer.
Allan agreed that Facebook's hiring of the consultants, a firm known as Definers, "damaged public trust", but said former policy VP Elliot Schrage-who was recently replaced by former United Kingdom deputy prime minister Nick Clegg-took responsibility for that decision.
"The engineers who had flagged these initial concerns subsequently looked into this further and found no evidence of specific Russian activity", Facebook said in a statement provided to AFP.
"Perhaps the best regulation is anti-trust", Angus said.
In response, Allan said at the hearing that the documents generally are "potentially misleading".
"I'm not going to disagree with you that we've damaged public trust through some of the actions we've taken", Allan told the hearing.
Nathaniel Erskine-Smith, another member of the Canadian Parliament, pressed Allan over whether a user signing up for Facebook could reasonably be seen as "meaningful consent" - the standard under Canadian privacy law - for the company allowing others to access that data. In August, Facebook temporarily suspended over 400 apps over concerns they may have mishandled users' personal data.
"This has generally been Facebook's answer to questions about its post-consent decree privacy practices".