U.S. border agents should not be able to search travelers' laptops without a reasonable suspicion of illegal activity, despite a court ruling allowing such searches, two groups said.

The Electronic Frontier Foundation (EFF) and the Association of Corporate Travel Executives (ACTE) filed an amicus brief on Thursday with the 9th Circuit Court of Appeals, asking the full court to rehear and reverse a decision by a three-judge panel that ruled that border agents can routinely search files on laptops and mobile devices.

The random searching of laptops is "widespread," said Lee Tien, senior staff attorney with the EFF. The U.S. Department of Justice "claims that U.S. border agents have the power to do so, no suspicion needed, and there are plenty of reported incidents," he added.

There have been multiple media reports in recent months of laptops or other electronic devices searched and seized at U.S. borders, Tien noted. In some cases, travelers have not gotten their electronic devices back from customs officials, he said.

The case the two groups have asked the court to review involves a U.S. man named Michael Arnold, who returned to Los Angeles International Airport from the Philippines in July 2005. A U.S. Customs and Border Patrol officer asked to see Arnold's laptop, and customs officers found pictures of naked women and, later, pictures they believed to be child pornography.

Customs officials seized Arnold's laptop and later had him arrested.

Arnold's lawyer argued that the search violated the U.S. Constitution's Fourth Amendment, prohibiting unreasonable searches and seizures. His lawyer argued that the pictures obtained in the search should not be allowed as evidence in a trial, and a judge in the U.S. District Court for the Central District of California agreed with Arnold's lawyer.

However, the three-judge panel at the 9th Circuit overturned the district court's ruling. U.S. border agents have broad authority to search luggage and their contents at borders, Circuit Judge Diarmuid O'Scannlain wrote in the panel's April 21 decision.

"Courts have long held that searches of closed containers and their contents can be conducted at the border without particularized suspicion under the Fourth Amendment," O'Scannlain wrote. "We are satisfied that reasonable suspicion is not needed for customs officials to search a laptop or other personal electronic storage devices at the border."

The EFF and ACTE argue in their brief that "invasive" searches of electronic devices should be treated differently from searches of luggage. "Your computer contains a vast amount of information about your private life, including details about your family, your finances, and your health," Tien said. "All that information can be easily copied, transferred, and stored in government databases, just because you were chosen for a random inspection."

Tien said he expects a decision on whether to rehear the case within a few months.

Asked if defending an alleged child pornography user was a tough place to make a stand on laptop searches, Tien disagreed. "If they randomly search your machine, don't find anything interesting, and let you go, would you sue them?" he said.