He was in Atlanta so he can be charged with a Georgia law even if it was the feds are involved. The federal law is quite similar though so it doesn't really matter.

> 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 under title 11, 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.

I'm not a lawyer, but I think the federal law might be more damning since the law clearly doesn't state that there has to actually be anything of value on the device as long as there was "intent to impede, obstruct, or influence the investigation". Wiping a phone that they want to look at will impede the investigation.