Mail Theft is a Non-technology identity fraud scheme that occurs when someone targets a victim’s mailbox and removes mail that has pertinent information on it.
As in dumpster diving, a thief can take your credit card bills, bank statements; anything that can be used to steal your identity.
At times, identity theft criminals, as part of mail theft have been known to re-route your mail without your knowledge or permission by submitting a change of address to the post office.
Ref.: http://www.utica.edu/academic/institutes/cimip/idcrimes/schemes.cfm