The answer to the headline question is yes. About two weeks ago, the FBI evoked FOIA exemption 7(a) and denied access to all Bain Capital records on the grounds that "there is a pending or prospective law enforcement proceeding relevant to these responsive records; and that release of the information contained in these responsive records could reasonably be expected to interfere with the enforcement proceedings."
Whether or not this "enforcement proceeding" target Bain Capital founder Mitt Romney is unknown.
FBI Response to FOIA Re: Bain Capital
An Aside
Some have asked in response to other FBI FOIA request related postings on this site whether the FBI is required to release files related to an open investigation. As this response shows, the answer to that question is no. However, the response also shows that the FBI is required to acknowledge their existence. The only time Bureau is allowed to claim a no records response is during an active investigation in which acknowledgment of responsive records would compromise it.
Whether or not this "enforcement proceeding" target Bain Capital founder Mitt Romney is unknown.
FBI Response to FOIA Re: Bain Capital
An Aside
Some have asked in response to other FBI FOIA request related postings on this site whether the FBI is required to release files related to an open investigation. As this response shows, the answer to that question is no. However, the response also shows that the FBI is required to acknowledge their existence. The only time Bureau is allowed to claim a no records response is during an active investigation in which acknowledgment of responsive records would compromise it.