(CNN) Senate Judiciary Chairman Charles Grassley, an Iowa Republican, has taken interest in why an early draft of a memo by then-FBI Director James Comey described the behavior of Hillary Clinton as "grossly negligent" for her handling of classified information, though Comey in his July 5, 2016 public statement didn't use that term.

A source familiar with the FBI decision tells CNN that Comey and his FBI colleagues were "playing with the language throughout" the process, but consistently held the belief that they needed to condemn Clinton's handling of classified information while asserting they would not bring charges.

Instead, Comey ended up criticizing Clinton's conduct as "extremely careless," but said no reasonable prosecutor would pursue charges based on the evidence.

"Although we did not find clear evidence that Secretary Clinton or her colleagues intended to violate laws governing the handling of classified information, there is evidence that they were extremely careless in their handling of very sensitive, highly classified information," Comey said in July.

JUST WATCHED FBI director: Clinton 'extremely careless' with emails Replay More Videos ... MUST WATCH FBI director: Clinton 'extremely careless' with emails 00:51

"Grossly negligent," the language dropped from the draft, is a term that carries with it legal ramifications. "Extremely careless," the term Comey ended up using, does not. So why the change?

Read More