The U.S. government has obtained a controversial type of secret court order to force Google Inc. and small Internet provider Sonic.net Inc. to turn over information from the email accounts of WikiLeaks volunteer Jacob Appelbaum, according to documents reviewed by The Wall Street Journal.

Sonic said it fought the government's order and lost, and was forced to turn over information. Challenging the order was "rather expensive, but we felt it was the right thing to do," said Sonic's...