A short cut investigation would be to demand Gerstein give up his source and upon refusal jail, him for contempt until he does.
We can't do that. During Obama's overt reign of terror a Fox reporter was harassed by digital snooping and investigations, and the right wing justifiably howled.
Reporters protecting sources is a long First Amendment tradition that in the past contributed to good investigative journalism. Because everything has gone to hell is no reason to throw it out, as people want to do to the Electoral College. Soon there would be nothing left but vigilantism and assassinations.