And hiding information from an FBI investigation certainly appears to be a problem.
From Murray Waas at The American Prospect Online:
White House deputy chief of staff Karl Rove did not disclose that he had ever discussed CIA officer Valerie Plame with Time magazine reporter Matthew Cooper during Rove’s first interview with the FBI, according to legal sources with firsthand knowledge of the matter."This means never compromising those rules."
The omission by Rove created doubt for federal investigators, almost from the inception of their criminal probe into who leaked Plame's name to columnist Robert Novak, as to whether Rove was withholding crucial information from them, and perhaps even misleading or lying to them, the sources said.
Also leading to the early skepticism of Rove's accounts was the claim that although he first heard that Plame worked for the CIA from a journalist, he said could not recall the name of the journalist. Later, the sources said, Rove wavered even further, saying he was not sure at all where he first heard the information.