The controversial order forced Google Inc. and small Internet provider Sonic.net to turn over the information from the e-mail accounts of WikiLeaks volunteer Jacob Appelbaum, documents reviewed by the Journal show.
Sonic said it fought the order and lost, forcing it to turn over the information. Google would not comment.
The Journal said the government's request included the e-mail addresses of people with whom Appelbaum has corresponded in the past two years, but not the full e-mails.
Appelbaum, 28, developed the Tor Project Inc., a Walpole, Mass., non-profit that provides free tools to help people remain anonymous online. People often use Tor to anonymously submit documents to WikiLeaks. Appelbaum has not been charged with any wrongdoing.
The 1986 Electronic Communications Privacy Act allows the government to secretly obtain information from people's e-mail accounts and cellphones without a search warrant. Some court decisions have raised questions about whether the law violates Fourth Amendment protections against unreasonable searches and seizures.
Some technology companies, including Google, have banded together to lobby Congress to update the law so it requires search warrants in more digital investigations.
The Journal notes the law was meant to provide the same protections for electronic communications as for phone calls and regular mail, but the law predated technology in which cellphones transmit locations and people store documents on remote services like Gmail instead of on their computers.
The act lets law enforcement get a hold of some e-mails, cellphone-location records and other digital documents without a search warrant showing probable cause to believe a crime was committed. Instead, under the 1986 communications law, government must demonstrate only "reasonable grounds" records would be "relevant and material" to an investigation, the Journal said.
In searches conducted under the law, the person whose e-mail is inspected often never knows it because court orders allowing the searches are almost always sealed and the Internet provider is typically forbidden to notify the customer whose data is searched.