Durham scrutinizing four key figures in Trump-Russia investigation

The secretive Justice Department inquiry into the Trump-Russia investigation's origins now includes former CIA Director John Brennan, former Director of National Intelligence James Clapper, former FBI special agent Peter Strzok, and British ex-spy Christopher Steele.

U.S. Attorney John Durham, whose investigative portfolio recently expanded to include events from the launch of the inquiry in 2016 through the appointment of special counsel Robert Mueller in 2017, has taken overseas fact-finding trips. But Durham's focus on the actions taken by specific individuals makes his mission look like it could transform into a criminal investigation. And the line of questioning Durham has taken with potential witnesses — some in line with claims made by President Trump and other Republicans — puts his efforts into sharper focus.

Brennan, a strident Trump critic, told NBC News that Durham wants to interview him and Clapper as Durham looks into the intelligence community's actions as it examined possible ties between the Trump campaign and the Kremlin. Brennan and Clapper led the Obama administration's intelligence agencies when some Republicans allege the CIA illicitly ensnared members of the Trump campaign using informants, though Democrats have dismissed this. Brennan and Clapper played leadership roles in the intelligence community’s assessment of Russian election interference in 2016.