Feds look into data handling by Facebook

The Federal Trade Commission has opened an investigation into whether Facebook violated an agreement with the agency on data privacy, after reports that information on 50 million users was improperly obtained by the political consulting firm Cambridge Analytica, according to a person with knowledge of the inquiry.

The investigation, started in recent days, adds to the mounting pressure against Facebook about its handling of the data. Cambridge Analytica used the information to help President Donald Trump’s presidential campaign profile voters during the 2016 election.

The scrutiny of the company now extends from state capitals to Europe. Attorneys general in Massachusetts and New York are investigating Facebook’s handling of personal data, and the British Parliament has called for a hearing with Mark Zuckerberg, the company’s chief executive. Several senators have also called for him to appear in Washington.

Adding to concerns about the company is the impending departure of Alex Stamos, Facebook’s chief security officer. That change, reported Monday by The New York Times, reflects heightened leadership tension at the company.

The buildup of news has already hurt Facebook’s stock. The company’s shares were down more than 9 percent in trading Monday and Tuesday.

The FTC investigation is connected to a settlement the agency reached with Facebook in 2011. The agency had accused the company of deceiving customers ‘‘by telling them they could keep their information on