In April 2016, a lawyer representing Hillary Clinton's campaign and the Democratic National Committee retained the services of a Washington firm to conduct research into President Trump's business interests, which led to the compilation of a dossier with allegations about Trump's connections to Russia, several people with knowledge of the matter told The Washington Post.
Congressional Republicans have been pushing for the firm, Fusion GPS, to reveal who paid for the research; it has refused, citing confidentiality agreements. The Post reports that lawyer Marc E. Elias retained Fusion GPS in April 2016. Before then, during the GOP primary, the company's research into Trump was funded by a Republican donor whose identity remains unknown. This person paid Fusion GPS to investigate Trump's background, and it was quickly determined that Trump had deep ties to Russia, several people told the Post.
Fusion GPS hired former British intelligence officer Christopher Steele to conduct the research, and it was his reports and documents that were compiled to make the dossier, which BuzzFeed News published in January; Fusion GPS denies giving BuzzFeed the dossier. The dossier claims the Russian government has compromising information on Trump and helped his presidential campaign, allegations Trump has denied. U.S. intelligence has corroborated some of the details in the dossier.
Perkins Coie, Elias' firm, funded Fusion GPS's research through the end of October. Fusion GPS gave Steele's reports and documents to Elias, several people told the Post, but it's unclear how much was passed along to the Clinton campaign and DNC, or who knew about the roles of Fusion GPS and Steele. The Clinton campaign and DNC never directed Steele's activities, the Post reports, and it is standard practice for campaigns to use law firms to hire outside researchers, so their work is protected by attorney-client and work-product privileges.