When the Tax Division declines a matter that the IRS referred to it for prosecution, the IRS can take whatever administration action it thinks is appropriate under the circumstances, including further investigation by CI. Should CI chose to investigate the declined matter further, its agents can use IRS summonses when conducting that investigation. 26 U.S.C. § 7602(d). The IRS may resubmit the matter to the Tax Division as a new referral.
[Updated September 2007] [cited in USAM 6-4.110]