Facebook Inc. has handed over to special counsel Robert Mueller detailed records about the Russian ad purchases on its platform that go beyond what the company shared with Congress last week, according to people familiar with the matter.

The information Facebook shared with Mr. Mueller included copies of the ads and details about the accounts that bought them and the targeting criteria they used, the people familiar with the matter said. Facebook policy dictates it would only turn over “the stored contents of any account,” including messages and location information, in response to a search warrant, some of them said.

A search warrant from Mr. Mueller would mean the special counsel now has a powerful tool to probe the details of how social media was used as part of a campaign of Russian meddling in the U.S. presidential election. Russia has denied any interference in the election.

Facebook hasn’t shared the same information with Congress in part because of concerns about disrupting the Mueller probe and possibly running afoul of U.S. privacy laws, people familiar with the matter said.

A Facebook spokesman said the company continues to investigate and is cooperating with U.S. authorities. A spokesman for Mr. Mueller declined to comment on the investigation.


Last week, Facebook disclosed that it identified about 500 “inauthentic” accounts with ties to Russia that bought $100,000 worth of ads during a two-year period encompassing the presidential campaign. The company also found $50,000 in ad purchases linked to Russian accounts. The combined funds purchased more than 5,000 ads on Facebook, the company said.

The disclosure was Facebook’s first acknowledgment that Russians used its platform to reach U.S. voters during the presidential campaign. It came about two months after Facebook said it had no evidence of Russian ad purchases.

In recent weeks, social media’s role in disseminating false information or inflaming public opinion has become a prime focus of the Senate and House intelligence committees, which are conducting separate probes into Russia’s influence on the election as well as whether President Donald Trump’s campaign or associates colluded with the Kremlin. The committees are aiming to write comprehensive public reports on Russian activity during the 2016 campaign.

﻿ ﻿ Mr. Trump has denied any collusion.


Twitter Inc. is also expected to speak to congressional investigators in the coming weeks about Russian activity on its platform, said Sen. Mark Warner of Virginia, the top Democrat on the Senate Intelligence Committee last week. A spokeswoman for Twitter declined to comment on whether the company had received any warrants or handed anything over related to possible Russian ad buys.

Alphabet Inc.’s Google unit said in a statement, “We’re always monitoring for abuse or violations of our policies and we’ve seen no evidence this type of ad campaign was run on our platforms.” A person familiar with the matter said the company hasn’t been called to testify on the topic.

Congressional investigators have been frustrated by how little detail Facebook provided in its briefing to them about the Russian ad buying, people familiar with the meetings said. In a briefing with Senate and House staffers last week, Facebook officials showed half a dozen examples of ads purchased by the Russian groups, the people said. After the briefing, Facebook staffers retrieved all the material used in the presentation, leaving staffers with just their notes, the people said.

Academic researchers and others also have criticized Facebook for not sharing more about the Russian ad-buying with the public beyond the roughly 720-word post it published last week. The post said the majority of the ads Facebook identified didn’t reference the election, voting or either presidential candidate, and mostly focused on “amplifying divisive social and political messages” on topics ranging from immigration to gun rights.


Facebook officials are wary of sharing more details with the public and intelligence committees for fear that public disclosure of information could disrupt Mr. Mueller’s probe, people familiar with the matter said. Facebook also believes the data about the ads could be protected under the Electronic Communications Privacy Act, one of the people said.

Handing over information or sharing it publicly without a valid legal order also could set a precedent for Facebook that would complicate its operations in the U.S. and world-wide, including in more authoritarian countries, the people said.

Sen. Richard Burr (R., N.C.), chairman of the Senate Intelligence Committee, and Mr. Warner are discussing plans to call representatives from Facebook to Capitol Hill to publicly explain how Russians manipulated the Facebook platform through paid and free posts to inflame U.S. public opinion and interfere in domestic politics.

Though negotiations are continuing and no final decision has been made, a Senate hearing on the role foreign governments played on social media is likely to be scheduled in coming weeks, according to the bipartisan leadership of the Senate committee.


Behind the scenes, details are still being worked out about the hearing, including gathering documents and facts that will inform the questions asked by members. A person close to the congressional investigation said both intelligence committees typically seek voluntary cooperation from potential witnesses before resorting to subpoenas. A subpoena hasn’t been ruled out, that person said.

Congress broadly has the power to subpoena documents and compel witnesses to appear before its committees to testify as part of a broad mandate to gather information.

According to Facebook’s policy, under U.S. law, a subpoena directed at the company would only allow access to “basic subscriber records” for a given account, including its name, when it was created, credit card information and, if available, the internet protocol address of where the user or page recently logged in or out.

A search warrant is a more powerful tool that would compel Facebook to disclose more detailed information about various accounts, such as messages, photos, videos, timeline posts, and location information.

According to a January report from the U.S. intelligence community, the highest levels of the Russian government were involved in directing the electoral interference to boost Mr. Trump at the expense of his Democratic rival Hillary Clinton.

Russia’s tactics included efforts to hack state election systems; infiltrating and leaking information from party committees and political strategists; and disseminating through social media and other outlets negative stories about Mrs. Clinton and positive ones about the Mr. Trump, the report said.

—Robert McMillan and Del Quentin Wilber contributed to this article.