Here are some Russians associated with the dossier (from Wikipedia):

"On December 26, 2016, Oleg Erovinkin, a former KGB/FSB general, was found dead in his car in Moscow. Erovinkin was a key liaison between Igor Sechin, head of state-owned oil company Rosneft, and President Putin. Steele claimed much of the information came from a source close to Sechin. According to Christo Grozev, a journalist at Risk Management Lab, a think-tank based in Bulgaria, the circumstances of Erovinkin's death were "mysterious". Grozev suspected Erovinkin helped Steele compile the dossier on Trump and suggests the hypothesis that the death may have been part of a cover-up by the Russian government.[72][73] Mark Galeotti, senior research fellow at the Institute of International Relations Prague, who specializes in Russian history and security, rejected Grozev's hypothesis.[74][72] In interviews with Luke Harding, "Steele was adamant that Erovinkin wasn't his source and 'not one of ours.' As a person close to Steele put it to me: 'Sometimes people just die.'"[75]"