British Parliament has seized a cache of documents that Facebook has spent months fighting in a California court to keep sealed, the latest effort by the U.K. to force the social media company to answer questions over privacy and the spread of "fake news." The documents are part of a lawsuit in which a small app developer is suing Facebook.

The app developer, Six4Three, and media outlets have long sought to make the documents public. A San Mateo, California Superior Court judge has ruled the documents sealed. Now a Parliament committee has them, and will decide soon what to do with them.

The founder of Six4Three, Ted Kramer, was in London last week when Parliament asked for the documents in a letter from Damian Collins, Chair of Parliament's Digital, Culture, Media and Sport Committee.

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"We are requesting these documents because we believe that they contain information that is highly relevant to our ongoing investigation into disinformation and fake news," read the letter. "In particular, we are interested to know whether they can provide further insights to the committee about what senior executives at Facebook knew about concerns relating to Facebook users' data privacy, and developers' access to user data."

Collins said in an email to CBS News that Kramer didn't comply with Parliament's request at first.

"We did not threaten him with fines or imprisonment but reminded that failure to comply could lead to him being investigated for being in contempt of parliament," Collins wrote. "I have reviewed the documents and the committee will make a statement next week on how we intend to proceed," Collins said.

In a tweet Sunday, Collins noted that his committee has the right to publish the documents.

The @CommonsCMS has received the documents it ordered from Six4Three relating to Facebook. I have reviewed them and the committee will discuss how we will proceed early next week. Under UK law & parliamentary privilege we can publish papers if we choose to as part of our inquiry — Damian Collins (@DamianCollins) November 25, 2018

The Observer newspaper in London first reported on the document seizure Saturday. It is not clear what the documents show.

Before suing Facebook, Six4Three created an app called Pinkini, which allowed Facebook users to search their friends' photos for them wearing bikinis. The company sued Facebook after the social media site changed its policies in 2015, effectively eliminating the Pinkini app's access to data it needed to operate.

In the lawsuit, Six4Three claims Facebook threatened to shut down data access to companies unless they complied with tough demands. Among them: That they purchase "advertising services from Facebook" or that a developer feed "all of its data back to Facebook."

A Facebook spokesperson called the lawsuit "entirely meritless" when asked to comment on Parliament's decision to seize the documents.

"Facebook has never traded Facebook data for anything and we've always made clear that developer access is subject to both our policies and what info people choose to share. We operate in a fiercely competitive market in which people connect and share," the Facebook spokesperson wrote. "For every service offered on Facebook and our family of apps, you can find at least three or four competing services with hundreds of millions, if not billions, of users."

On Tuesday, Collins will lead an unprecedented "international grand committee" of lawmakers from seven countries investigating Facebook and the spread of "fake news."

The group, which includes representatives from the U.K., Canada, Ireland, Argentina, Brazil, Latvia and Singapore will question Richard Allan, Facebook's vice president of policy solutions, before signing a set of "International Principles for the Law Governing the Internet."

The lawmakers have repeatedly tried to get testimony from Facebook CEO Mark Zuckerberg, who has steadfastly refused to appear before Parliament. Facebook has pointed to Zuckerberg's appearances before Congress and the European Union Parliament, arguing that he can't visit every legislature investigating Facebook.

Allan noted in a letter to Collins Sunday that Six4Three is challenging Facebook's efforts to restrict access to user data. Facebook provided his letter to CBS News.

"We have faced extensive criticism over the last few months for the fact that the app ThisIsYourDigitalLife, which your committee has looked at extensively, was able to access data shared with an installer of the app by their friends. We explained that we moved to restrict such access to friend data when we updated the API used by 3rd party developers over the period 2014 to 2015," Allan wrote. "This change was a significant one affecting thousands of applications and was communicated to them clearly and in advance. On earlier occasions, your Committee appeared to endorse this more restrictive approach. If this has now changed, it would be useful to understand why."

Allan said in the letter that while he expects to be questioned about Six4Three files during the "grand committee" hearing Tuesday, he is "also mindful that this matter is sub judice before a court in California," meaning that it is under judicial consideration.

Collins responded to Allan's letter in an email, which was also provided to CBS News.

"As you know, we have asked many questions of Facebook about its policies on sharing user data with developers, how these have been enforced, and how the company identifies activity by bad actors. We believe that the documents we have ordered from Six4Three could contain important information about this which is of a high level of public interest," Collins wrote. "We are also interested to know whether the policies of Facebook, as expressed within these documents, are consistent with the public statements the company has made on the same issues."

The seizure of documents and "grand committee" hearing comes just weeks after a Nov. 5 report in which Britain's Information Commissioner concluded "Facebook... failed to keep [users'] personal information secure because it failed to make suitable checks on apps and developers using its platform."