Hugh Hewitt explained the departure of David Laughman on Twitter, as noted on the Washington Post. Via Twitchy:
"He likely had a role in the decision[-]making on the Clinton email investigation since his section handled cases involving leaks of classified information. The decisions on granting immunity, and allowing conditions to be attached to the examination of computers, would have come from his office. I do not think those were conditions that the FBI would have wanted. On the immunity issue, FBI wouldn't have the authority – that could ... come from [only] the prosecutors in Nat Sec.
"Dave[,]" aka David Laufman (DOJ – National Security Division, [d]eputy [a]sst. [a]ttorney [g]eneral in charge of counterintelligence)[,] quit yesterday.
"Trisha[,]" aka Trish Beth Anderson (Office of Legal Counsel, FBI)[.]