James Comey told ABC News he thinks there might be evidence of obstruction of justice against President Donald Trump.
"Was President Trump obstructing justice?" ABC News' George Stephanopoulos asked James Comey. "Possibly. It's certainly some evidence of obstruction of justice," Comey said.
It all links back to a conversation between Comey and Trump that happened in February 2017.
According to the former FBI director, Trump was talking about the investigation into Michael Flynn when the president said, "He's a good guy. I hope you can let this go."
Comey took that statement as a request to drop the criminal investigation into the former National Security Adviser, who later pleaded guilty to lying to the FBI during the Russia investigation.
Obstruction of justice concerns popped up when word of that conversation first got out in May.
Then they were renewed after a December tweet from Trump's Twitter account said he fired Flynn because he lied to the FBI.
Some experts say that if Trump knew Flynn lied to the FBI before he left the administration, asking Comey to stand down could have been obstruction. Trump's personal lawyer later claimed he wrote that tweet.
Trump denied asking Comey to drop the Flynn investigation.