According to a federal court in the Northern District of California, United States border agents may not search a laptop without a warrant several months after the agents seized the laptop.

Upon arriving at San Francisco International Airport from Seoul, South Korea in late January 2009, the U.S. Customs and Border Protection randomly selected Andrew Hanson for secondary screening.  Due to his allegedly suspicious behavior, a border agent searched Mr. Hanson’s laptop, among other things, and found a photo that the agent believed to be child pornography.  Border agents then searched the contents of the laptop two other times:  once in mid-February, after sending the laptop to a U.S. Customs and Border Protection lab for copying and inspection, and again in June, the latter search revealing over 1,000 images of child pornography.  Hanson challenged the validity of the these two warrantless searches. 

Consequently, while warrantless searches of laptops conducted at the border, or soon thereafter, are permissible, searches occurring months after the initial border search may require probable cause and a warrant.