45 C.F.R. § 689.6 – Investigations.

(a) When an awardee institution or another Federal agency has promptly initiated its own investigation, OIG may defer an NSF inquiry or investigation until it receives the results of that external investigation. If it does not receive the results within 180 days, OIG may proceed with its own investigation.
(b) If OIG decides to initiate an NSF investigation, it must give prompt written notice to the individual or institutions to be investigated, unless notice would prejudice the investigation or unless a criminal investigation is underway or under active consideration. If notice is delayed, it must be given as soon as it will no longer prejudice the investigation or contravene requirements of law or Federal law-enforcement policies.
(c) If a criminal investigation by the Department of Justice, the Federal Bureau of Investigation, or another Federal agency is underway or under active consideration by these agencies or the NSF, OIG will determine what information, if any, may be disclosed to the subject of the investigation or to other NSF employees.
(d) An NSF investigation may include:
1. (1) Review of award files, reports, and other documents already readily available at NSF or in the public domain;
2. (2) Review of procedures or methods and inspection of laboratory materials, specimens, and records at awardee institutions;
3. (3) Interviews with subjects or witnesses;
4. (4) Review of any documents or other evidence provided by or properly obtainable from parties, witnesses, or other sources;
5. (5) Cooperation with other Federal agencies; and
6. (6) Opportunity for the subject of the investigation to be heard.
(e) OIG may invite outside consultants or experts to participate in an NSF investigation. They should be appointed in a manner that ensures the official nature of their involvement and provides them with legal protections available to federal employees.
(f) OIG will make every reasonable effort to complete an NSF investigation and to report its recommendations, if any, to the Deputy Director within 180 days after initiating it.