Absolutely.
The FBI can be brought into the investigation...
Upon written request of the Department, the FBI also investigates perjury violations committed in connection with any inquiry or investigation being conducted by the United States House of Representatives or the United States Senate, or their components.
http://www.usdoj.gov/usao/eousa/foia...9/crm01742.htm
...and if the DoJ Inspector General is of the opinion that there is reasonable evidence that Gonzales lied under oath in his testimony at Congressional hearings, he can recommend to the Acting AG (and Bush) that a special prosecutor present a case to a grand jury.
I think it important for the integrity of the Dept of Justice that this plays out to the fullest extent possible.