Sen. Chris Coons (D-Del.) said Thursday he fears President Trump fired FBI Director James Comey because Comey’s investigation into Russian interference in the U.S. presidential election started to get too close to the truth.

“This FBI investigation is picking up speed, and my concern, and the concern of many of my colleagues, is that the FBI director was fired because he was beginning to get too close,” Coons told CNN’s “New Day.” 

{mosads}Trump said he fired Comey at the recommendation of Attorney General Jeff Sessions and Deputy Attorney General Rod Rosenstein, who questioned the FBI head’s judgment after his handling of the investigation into Democratic presidential nominee Hillary Clinton’s use of a private email server while secretary of State.

Coons said the firing could be an attempt to thwart the investigation into whether Trump campaign aides colluded with Russian officials to sway the election in Trump’s favor.

“This is a deeply concerning moment where either the president has fired the FBI director because he didn’t like how he treated Hillary Clinton or there’s a real attempt at obstructing justice going on here,” he added.

Coons praised FBI professionals, saying thousands are dedicated public servants. 

He said his concern is Sessions’s continued involvement in the investigation after he recused himself from involvement in probes into Russian interference. 

“My concern is that this looks like a politically motivating firing. Where an attorney general, who had recused himself, interjected himself. Where a president who had personal motivations to try to end an investigation into collusion between his campaign and the Russians, took a politically motivated action,” Coons said.

“If we can’t clear that cloud, how will the public, how will those of us in the Senate have confidence in whatever conclusion the FBI reaches?”