WASHINGTON — Bill Hogan was returning home to the U.S. from Germany in February when a customs agent at Dulles International Airport pulled him aside. He could reenter the country, she told him. But his laptop couldn’t.

U.S. Customs and Border Protection agents said he had been chosen for “random inspection of electronic media,” and kept his computer for about two weeks, recalled Hogan, 55, a freelance journalist from Falls Church, Va.

Fortunately, it was a spare computer that had little important information. But Hogan felt violated….