UPDATE: Limited detail has emerged after Schiller's Tuesday testimony. However, CNN reports Trump's longtime personal bodyguard denied "the salacious claims about Trump's 2013 trip to Moscow that appeared in the opposition research Russia dossier about Trump" and "said little...telling lawmakers repeatedly that he could not recall or was not aware a number of potential Russia connections with Trump associates, which Democrats continually asked about."
Key Trump ally Schiller denies dossier claims in House testimony (CNN)
Keith Schiller, President Trump's longtime bodyguard and former director of Oval Office Operations, will speak with the House Intelligence Committee Tuesday:
WaPo:
Investigators plan to press Schiller about allegations in the 35-page dossier that Russian officials obtained compromising information about Trump’s personal behavior when he visited Moscow for the 2013 Miss Universe pageant, according to people familiar with the investigation.
(...)
The House panel also plans to ask Schiller about another episode that is a central focus in the investigations by congressional committees and special counsel Robert S. Mueller III: the firing of former FBI Director James B. Comey.
Trump tasked Schiller with hand-delivering to the FBI the president’s letter terminating Comey. Investigators are examining whether Trump was attempting to obstruct the criminal investigation into Russian meddling by firing Comey.
Schiller left the White House in September.
Longtime Trump bodyguard to face questions about 2013 Moscow trip (WaPo)