United States lawmakers are calling for more regulation of Facebook.The move comes after reports that the social media companymay have let a political organization have access to personal datafrom around 50 million Facebook users in 2014.Facebook wrote about the issue on Friday in a public online message,just before news media began reporting on the story.Reports said that Cambridge Analytica was given access to the data.The data company is linked to conservatives and is knownfor its work on Donald Trump's 2016 presidential campaign.The reports also say the company may not have deleted, or removed, the data.Democratic U.S. Senator Amy Klobuchar wrote on Twitterthat it is clear that companies like Facebook cannot "police themselves."She added that Facebook chief Mark Zuckerbergshould speak before the Senate Judiciary committee.Facebook announced late Friday it was banning Cambridge Analyticafrom its service for misusing data.The reports are the latest threat to Facebook's public image.It has been criticized over Russia's use of Facebookto influence American voters during the 2016 election.Facebook said researchers and Cambridge Analyticalied to the company and abused its policies.Yet critics are blaming Facebook.They are also demanding answers for userswhose information was given to Cambridge Analytica.Facebook claims the data was misused, not stolen.It says users gave it permission.The company's position has led to a debateabout what is considered a "hack" that users must be told about.Frank Pasquale is a University of Maryland law professor.He has written about Silicon Valley's use of data.He said that Facebook's explanation that data had not been stolenavoided the central issue that data was used in a different way than users expected.Senator Mark Warner, a Democrat, said the eventproves the need for new regulations about internet advertising.He described the industry as the "Wild West."He said that without new regulations,the market will continue to deal with deception and secrecy.Both The New York Times and London's Observer reported Saturdaythat private information from more than 50 million Facebook userswas wrongly given to Cambridge Analytica.They also reported that the company had not deleted the data,even though Facebook told them to beginning in 2015.The reports say that about 270,000 Facebook usersgave a researcher permission to use their data.The researcher also took the data of all their friends,a move that was permitted based on Facebook's rules until 2015.The researcher then sold the data to Cambridge Analytica.That move was against Facebook rules, the newspapers said.Cambridge Analytica worked on Trump's 2016 campaign.However, a Trump campaign official said they used Republican data sources,not Cambridge Analytica, for voter information.Facebook said in a series of statements over the weekendthat researchers and Cambridge Analytica broke Facebook rules.It said it was considering legal action against them.In answer, Cambridge Analytica said that they had, in fact, deleted the data.It also said the company supplying the data was responsible for obtaining it.Andrew Bosworth, a Facebook vice president, said the companycould make more changes to demonstrate that it values privacy."We must do better and will," Bosworth wrote on Twitter.Nuala O'Connor is president of the Center for Democracy & Technology in Washington, D.C.She said Facebook was depending on the honesty of peoplerather than preparing for the planned misuse of data.O'Connor also added that Facebook knew about the abuse in 2015but did not inform users until Friday."That's a long time," she said.Massachusetts Attorney General Maura Healy said on Saturdayshe was launching an investigation into the use of Facebook data.Healey's office said she wants to understand how the data was used,what policies may have been abused,and what the legal effects are.