Special counsel Robert Mueller’s team will interview former White House chief strategist Steve Bannon by the end of the month, according to reports from CNN and NBC News out Wednesday.

Mueller’s investigators want to ask Bannon about the firings of FBI Director James Comey and National Security Adviser Michael Flynn, two people familiar with the probe told CNN.

It had been previously reported that Bannon agreed to sit for an interview with Mueller’s team after the special counsel issued a subpoena to Bannon, calling for him to testify before a grand jury. But CNN’s report shows that Mueller is looking to speak with Bannon soon.

CNN’s report also suggests that the Mueller team’s probe into potential obstruction of justice is heating up, given recent reports about the investigation’s direction. The special counsel team spoke with Attorney General Jeff Sessions last week for several hours. Sessions was involved in the Comey firing, one of the key narratives in the obstruction of justice probe. Mueller’s team is also reportedly looking to speak with President Donald Trump about the firings of Comey and Flynn, a sign that Mueller’s team is looking seriously at obstruction of justice.