A group of US senators is looking into Facebook's reported use of a Republican opposition-research firm to battle its critics.
Democratic Sens. Amy Klobuchar, Mark Warner, Chris Coons and Richard Blumenthal sent a letter to Facebook CEO Mark Zuckerberg on Friday to press the social network for more details about its relationship with Definers Public Affairs after the connection on Wednesday.
"We are gravely concerned by recent reports indicating that your company used contractors to retaliate against or spread intentionally inflammatory information about your critics," reads the letter.
Klobuchar told the Senate Judiciary Committee on Thursday that the use of such a firm could raise campaign finance issues.
"I would like to know what was going on with elected officials," Klobuchar said, according to Reuters. "It could also have other legal ramifications."
Democratic Sen. Mazie Hirono also joined Klobuchar, Blumenthal and Coons in asking the Justice Department to "expand any investigation into Facebook and Cambridge Analytica to include whether Facebook -- or any other entity affiliated with or hired by Facebook -- retaliated against critics or public officials seeking to regulate the platform, or hid vital information from the public."
Definers reportedly targeted Klobuchar over, which would require Facebook and other tech companies to disclose who purchased political ads online.
Klobuchar's office didn't respond to a request for comment.
On Wednesday, the Times published a bombshell report about how Facebook's leaders struggled to deal with a series of crises, including Russian election interference and the mishandling of Facebook user data by Cambridge Analytica. The report says CEO Mark Zuckerberg and COO Sheryl Sandberg ignored warnings, deflected blame and got distracted by other projects as problems mounted over the past three years.
Zuckerberg said Thursday that he and Sandberg, and that the relationship was terminated as soon as they found out about it.
Definers didn't respond to a request for comment but said in a statement Friday that itas an opposition-research firm.
Facebook didn't respond to a request for comment.
First published Nov 16, 5:48 a.m. PT.
Update, 12 p.m.: Adds information from the senators' letter to Facebook.
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