Mohamed Shommo, an engineer for Cisco Systems, travels overseas several times a year for work, so he is accustomed to opening his bags for border inspections upon returning to the US. But in recent years, these inspections have gone much deeper than his luggage.
Border agents have scrutinised family pictures on Shommo's digital camera, examined Koranic verses and other audio files on his iPod and even looked up Google keyword searches he had typed into his company laptop.
"They literally searched everywhere and every device they could," said Shommo, who now minimises what he takes on international trips and deletes pictures off his camera before returning to the US "I don't think anyone has a right to look at my private belongings without my permission. You never know how they will interpret what they find."
Given all the personal details that people store on digital devices, border searches of laptops and other gadgets can give law enforcement officials far more revealing pictures of travellers than suitcase inspections might yield. That has set off alarms among civil liberties groups and travellers' advocates - and now among some members of Congress who hope to impose restrictions on the practice next year.
They fear the government has crossed a sacred line by rummaging through electronic contact lists and confidential email messages, trade secrets and proprietary business files, financial and medical records and other deeply private information.
These searches, opponents say, threaten Fourth Amendment safeguards against unreasonable search and seizure and could chill free expression and other activities protected by the First Amendment. What's more, they warn, such searches raise concerns about ethnic and religious profiling since the targets often are Muslims, including US citizens and permanent residents.
"I feel like I don't have any privacy," said Shommo, a native of Sudan who has been in the US for more than a decade and plans to apply for citizenship next year. "I don't feel treated equally to everybody else. I feel discriminated against."
Customs and Border Protection, part of the Department of Homeland Security, asserts that it has constitutional authority to conduct routine searches at the border - without suspicion of wrongdoing - to prevent dangerous people and property from entering the country. This authority, the government maintains, applies not only to suitcases and bags, but also to books, documents and other printed materials - as well as to electronic devices.
Such searches, the government notes, have uncovered everything from martyrdom videos and other violent jihadist materials to child pornography and stolen intellectual property.
While Homeland Security points out that these procedures predate the attacks of Sept. 11, 2001, civil liberties groups have seen an uptick in complaints about border searches of electronic devices in the past two years, according to Shirin Sinnar, staff attorney at the Asian Law Caucus.
In some cases, travellers suspected border agents were copying their files after taking their laptops and cell phones away for anywhere from a few minutes to a few weeks or longer.
Such inspections appear to amount to "a fishing expedition" by border agents, said Farhana Khera, executive director of Muslim Advocates.
These objections led the Asian Law Caucus and the Electronic Frontier Foundation to file a Freedom of Information request to obtain the federal policy on border searches of electronic devices. When the government failed to respond, the groups filed a lawsuit this year. And lawmakers began demanding answers.
So in July, amid the mounting outside pressure, Homeland Security released a formal policy stating that federal agents can search documents and electronic devices at the border without suspicion. The procedures also allow border agents to detain documents and devices for "a reasonable period of time" to perform a thorough search "on-site or at an off-site location."
The problem with this policy, argues Marcia Hofmann, staff attorney with the Electronic Frontier Foundation, is that the contents of a laptop or other digital device are fundamentally different than those of a typical suitcase.
As Sen. Ron Wyden, D-Ore., who is co-sponsoring one of several bills in Congress that would restrict such searches, put it: "You can't put your life in a suitcase, but you can put your life on a computer."
Susan Gurley, executive director of the Association of Corporate Travel Executives, which filed its own Freedom of Information request to obtain the government's laptop search policy, noted that border searches pose a particular concern for international business travellers. That's because they often carry sensitive corporate information on their laptops and don't have the option of leaving their computers at home.
And for many travellers, the concerns go beyond their own privacy or the privacy of their employers. Lawyers may have documents subject to attorney-client privilege. Doctors may be carrying patient records.
Tahir Anwar is an imam at a mosque in San Jose, California, so his laptop and iPhone contain confidential information about the mosque's members, including their personal email messages.
Anwar has travelled abroad 12 times over the past 2 1/2 years and he has been detained upon returning to the US every time. Border agents have searched his laptop and once took away his cell phone for 15 minutes.
Now when Anwar travels, he simply leaves his laptop behind and deletes email off his iPhone before crossing the border, synching it back up with his computer after he gets home.
"People tell me their innermost secrets," Anwar said. "I tell people to email me, so a lot of personal information is in my email. If people find out that this information is being looked at, I can't serve my purpose and people won't come to me."
For its part, the government argues that some of the most dangerous contraband is transported in digital form today - making searches of electronic devices a crucial law enforcement tool.
Among the successful searches the government cites from recent years: In 2006, a man arriving from the Netherlands at the Minneapolis airport had digital pictures of high-level Al-Qaida officials, and video clips of improvised explosive devices being detonated and of the man reading his will. The man was convicted of visa fraud and removed from the country.
"To treat digital media at the international border differently than Customs and Border Protection has treated documents and other conveyances historically would provide a great advantage to terrorists and others who seek to do us harm," Jayson Ahern, the agency's deputy commissioner, said in a statement submitted to the Senate Judiciary subcommittee on the Constitution in June. Homeland Security did not send anyone to testify.
Amy Kudwa, a spokeswoman for the department, also stressed that a tiny fraction of 1 per cent of all travellers are singled out for laptop searches at the border. She added that Homeland Security does not profile based on religion, race, ethnicity or any other criteria in conducting such searches.
So far, only a handful of court cases have addressed the issue.
Federal appeals courts in two circuits have upheld warrantless or "suspicionless" computer searches at the border that turned up images of child pornography used as evidence in criminal cases.
But late last year, a US magistrate judge in Vermont ruled that the government could not force a man to divulge the password to his laptop after a search at the Canadian border found child pornography. The US Attorney's Office in Vermont is appealing the decision to the US district court.
Now Congress is getting involved. A handful of bills have been introduced that could pass next year.
One measure, sponsored by Sen. Russell Feingold, D-Wis., chairman of the Constitution subcommittee, would require reasonable suspicion of illegal activity to search the contents of electronic devices carried by US citizens and legal residents. It would also require probable cause and a warrant or court order to detain a device for more than 24 hours.
And it would prohibit profiling of travellers based on race, ethnicity, religion or national origin.
Rep. Eliot Engel, D-N.Y., is sponsoring a bill in the House that would also require suspicion to inspect electronic devices. Engel said he is not trying to impede legitimate searches to protect national security. But, he said, it is just as important to protect civil liberties.
"It's outrageous that on a whim, a border agent can just ask you for your laptop," Engel said. "We can't just throw our constitutional rights out the window."