If an internet service provider $($ISP$)$ or any other communications network stores an email, retrieval of that evidence must be analyzed under $$ which creates statutory restrictions on government access to such evidence from ISPs or other electronic communications service providers.

$$ the Electronic Communications Privacy Act $($ECPA$)$

$18$ U$.$S$.$C$.2252$B

the Communications Assistance to Law Enforcement Act

the USA PATRIOT Act