The main source for Christopher Steele’s discredited dossier, Igor Danchenko, defended the years he spent working at the Brookings Institution, as special counsel John Durham scrutinizes the Washington, D.C., think tank and its ties to the former MI6 agent’s anti-Trump opposition research.

Durham used a subpoena to obtain documents from Brookings related to its employment of Danchenko, a U.S.-based and Russian-trained lawyer who visited Russia in 2016 as he worked for Steele. The New York Times reported last week that the former Connecticut federal prosecutor obtained records from the left-leaning think tank related to Danchenko, who worked for the organization from 2005 to 2010 as a Russia researcher but is best known as the “primary sub-source” for Steele’s Trump-Russia dossier in 2016.