The 31-year-old defendant was a de facto spokesman for Anonymous, willing to speak for a movement that prides itself on anonymity.
The latest indictment alleges that he concealed the laptops from authorities at the home of an associated identified only as "KM."
The indictment doesn't detail what was on the laptops. He already is accused of stealing data from the Austin-based private intelligence firm Stratfor and threatening an FBI agent on the Internet.
A message to Brown's attorney, Doug Morris, was not returned.