49 CFR 831.62: Access to and release of wreckage, records, mail, and cargo.

(a) Only persons authorized by the NTSB to participate in any particular investigation, examination or testing may be permitted access to wreckage, records, mail, or cargo.

(b) Wreckage, records, mail, and cargo in the NTSB's custody will be released when the NTSB determines it has no further need for such items. Prior to release, the NTSB will inform the USCG of the upcoming release of wreckage or evidence. Recipients of released wreckage must sign an acknowledgement of release provided by the NTSB.