The contest between law enforcement and the bomber who killed three and wounded more than 175 at the Boston Marathon on Monday is taking place in a very different arena from past investigations. Where the Unabomber used the deep woods and isolation to hide, the Boston bomber is using the anonymity of crowds and the open-source knowledge of the Internet in his attempt to elude justice. But over the past few years, the cops have learned to fight on that field too.
By all accounts, the FBI started cold on the case, meaning they had no prior information of the bomb plot to guide them as they began the hunt. From the start, the feds pursued traditional modes of investigation to begin generating the evidence for an eventual conviction of the murderer. They sealed the bomb site within minutes of the blast and soon enough found the telltale pieces of a pressure-cooker bomb of the kind favored by Islamic extremists and admired by right-wing militias.
At first, the bomber seemed to have the advantage. He had chosen a crowded public event as his target, making it hard for potential witnesses to differentiate him from thousands of innocent bystanders and increasing the likelihood that evidence might have been destroyed in the mayhem after the explosion. And he had used a crude but effective bomb design that is widely available on the Web, and the parts to which can be bought at major retail stores or at hardware stores.
But the cops have new tools to fight back against this approach, some of them the product of technological advances, others given to them by law after 9/11. Pressure-cooker bombs are sometimes detonated remotely by cell phone. If the bomber used that method, the FBI will have access to all calls made at or around the time of the explosions, thanks to detailed records of traffic through local cell towers that are routinely kept by carriers and are made available to law enforcement often without a court order (though in this case a subpoena would be easy to get).
The next big advantage for law enforcement is the proliferation of video cameras in recent years, both public and private. Investigators called on all those who took pictures and videos near the bomb site to review them for anything that could help investigators. “There has to be hundreds, if not thousands, of photographs, videos and other observations that were made down at that finish line yesterday,” says Timothy Alben, superintendent of the Massachusetts State Police. “You might not think it’s significant, but it might have some value to this investigation.”
And in reviewing tape from a local store in the area of the blast, the FBI reportedly identified one or more suspects who may have left the bags containing the bombs. Now with initial leads on suspects, law enforcement will try to identify them and gather evidence they committed the crime. Here they will have two possible avenues, one traditional and one with newer powers, depending on whether the suspects have foreign terrorist connections or not.
If investigators uncover a potential suspect who has no link to foreign terrorism, they will rely on the traditional warrants and subpoenas. These include Title III surveillance powers, which are strong — investigators can eavesdrop on a suspect at home and as he moves in public, for example. And if they can show probable cause that the suspect committed a crime, they can tap broad grand jury, administrative and other subpoena powers to obtain evidence from businesses and individuals.
If investigators can show a link to foreign terrorism, they can use so-called Section 215 search orders under the Patriot Act, which allow the FBI to take physical objects of any sort from individuals and businesses, including banking and phone records, and photographs, without a court order. They can also use National Security Letters to collect so-called noncontent records, like the subject and date information from e-mails, among other things, without a court order. Lastly, if a link to international terrorism is shown, Foreign Intelligence Surveillance Act powers are available, including longer surveillance and protections from revealing sources and methods in eventual court cases.
Perhaps the hardest question for law enforcement in this new arena will come after they believe they have enough evidence to convict a suspect. At that point, they could bust him and take him to trial, or they could continue surveillance in the hope of uncovering a larger network that might try to strike Americans again in the future. If the suspect is an international terrorist, intelligence agencies in Washington will push for gathering as much intelligence as possible against the larger threat from abroad, which could delay an arrest.