If they can make a solid connection if it was installed after the date of the subpoena, they may actually have something with some teeth finally.
18 US Code 1512 (c) 1519
Whoever knowingly alters, destroys, mutilates, conceals, covers up, falsifies, or makes a false entry in any record, document, or tangible object with the intent to impede, obstruct, or influence the investigation or proper administration of any matter within the jurisdiction of any department or agency of the United States or any case filed, or in relation to or contemplation of any such matter or case, shall be fined under this title, imprisoned not more than 20 years, or both.