washington despite public promise cooperation facebook social media company congressional investigators battle much data company hand russian efforts influence 2016 u.s. presidential election congressional source say week facebook inc fb.o slow cooperate company others say turn information also legally obligate protect users privacy visit capitol hill wednesday thursday sheryl sandberg facebook chief operate officer meet leaders house intelligence committee say company want help investigators would turn information things happen platform happen lead-up election sandberg tell axios website thursday far however congressional source say investigators find hard extract relevant information silicon valley allege russian activity committees far see need issue subpoena data source add facebook major internet company include alphabet inc google googl.o twitter inc twtr.n face stream recent revelations moscow seek use platforms sow discord unite state influence election favor republican white house candidate donald trump facebook disclose last month find 3,000 politically divisive advertisements believe buy russia presidential campaign company share congressional investigators ads information pay target facebook spokesman say sandberg tell congressional investigators thursday addition ads company would provide rest information account link russia spokesman say source say investigators also press twitter google company similar data urge twitter conduct comprehensive search data bank set strict ads policies include limit political ad target prohibitions target base race religion google spokeswoman say ask issue take deep look investigate attempt abuse systems work researchers company provide assistance ongoing inquiries twitter spokesperson respond email request comment twitter likely release potentially relevant data congressional investigators part policy require court order track record defend user privacy fight request adam sharp former head news government twitter say interview twitter engineer try regenerate lose data may able retrieve say person familiar company technology use social media platforms part u.s. intelligence agencies conclude broad russian effort meddle election campaign allegation kremlin deny several congressional committees well special counsel robert mueller investigate russian interference include potential collusion trump associate moscow trump deny collusion september facebook disclose evidence operation base russia spend 100,000 thousands sponsor post promote divisive social political message two-year period may 2017. facebook say believe message likely buy people russia 2016 election source familiar facebook contact congress say recently july year company officials deny existence pay russian message late acknowledge company find 100,000 sponsor traffic link 478 facebook account source say investigators think pay message generate group call internet research agency st. petersburg u.s. officials call troll factory create false identities copy real ones spread real skew fake information kremlin congressional source say facebook message go group seemingly legitimate name heart texas defend second unite muslims america say many 250,000 followers group appear bogus set look like legitimate political organizations investigators want learn group followers origins source say say facebook lawyers argue turn additional data could compromise promise privacy users however congressional investigators say russian messengers use fake identities would legal claim privacy u.s. congress tangle facebook social media firm russia probe