Stall.
Obfuscate.
Stonewall.
Sabotage.
Thwart.
Repeat...................
The committee has subpoena power. It can demand the info be turned over. Or else, jail the Director. Literally.
And then ask his deputy for the info. And repeat, if necessary.
Somewhere someone has to assert the people’s authority over the deep state, or else the Republic is dead.