The manhunt for Dzhokhar Tsarnaev and his brother Tamerlan, both suspects in the 2013 Boston Marathon bombings, was the most intense one the northeastern U.S. city had seen in a long time.

© Alexander Demianchuk/Reuters/Corbis

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Introduction to How Manhunts Work

He was about to become the most hated man in American, given the murder he had just committed. For the time being though, he had managed to slip out a door and into the night on horseback. More than a week later -- with a law enforcement agency and an actual army on his tail -- John Wilkes Booth had continued to evade capture by slipping across the Potomac, aided by sympathizers. But April 26, 1865, found Booth hiding in a Virginia farmhouse, where Union soldiers set fire to the structure and lured him to the porch, killing him in a shootout.

Like unhappy families, every on-the-lam criminal is on-the-lam in his or her own way. For example, Whitey Bulger, a Boston mobster who spent 16 years hiding from authorities to avoid criminal charges, was taken into FBI custody in Santa Monica after ambling out to his garage to inspect a storage locker. On the other hand, you have Osama bin Laden, who spent 10 years hiding from nearly every global security agency imaginable, taken down by an elite force of Navy SEALs.

And then there's your more run-of-the-mill manhunt, the kind we associate with cop shows: a criminal who initially eluded local police but, after some decent police work, is found within hours or days. Not something the FBI or Navy SEALs would deal with, but no small security matter in the community.

In this article, we'll take a look at several different types of manhunts, and get some inside information about the tactics used to Get Their Guy (or Girl). Buckle the seat belt in your pursuit car, as we tackle some of the basics of how manhunts take place.

Who's got the herb?

If you're in the United States and police knock on your door asking to come in to inspect for a suspect on the loose, you should probably hide your drug stash if you have one. There is a "plain view" doctrine that says if evidence of a crime is in sight, police can use it against you in court (even if they weren't setting out to find it).

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U.S. Manhunts: What You Need to Know

One of the first things that happens in a manhunt on a more regional scale is to set up containment -- a term that means one or more officers can see any exit the suspect might take. That doesn't always just mean that a couple of police officers eye the block. Vehicle checkpoints or K-9 units might be used to sniff out a perimeter. After that, law enforcement will quickly set up a command post, where officers (or the press) can be briefed. Note: Location can be tricky. If you happen to be reading this and setting up a command post, be sure that your suspect isn't close enough that he or she might hear the briefings. It's happened.

In the case of the 2013 manhunt for the Boston Marathon bombing suspects, the containment went far beyond the usual perimeter security. That was for some fairly significant reasons: First, the suspects were armed with explosives. Second, after one suspect died, the other fled into a residential neighborhood. The police solution in this case was to put up a containment area of 20 blocks, while shutting down public transportation and putting residents in the restricted area on lockdown in their homes. Most manhunt containments are a little more lenient though.

If you're caught in the midst of a lockdown during a U.S. manhunt, there are a few things you should know about your own rights. The law says the police can't just burst into your house looking for a suspect without probable cause. That means that if police see or hear something that gives them reason to believe the suspect is there, they can go in. (They are allowed to go through lawns and peer in windows.) They can also enter without permission if they need to provide emergency services. Of course, they can also go door-to-door (like in Watertown) and look around your house if you give them permission.

But here's the big one. Exigent circumstances (an emergency) might also allow them to enter a private residence -- and, arguably, a terror suspect armed with explosives might be the emergency that would impel officers to act without a warrant. The gamble is that if their intrusion is deemed unlawful later any admissible evidence is thrown out.

As you can imagine, not every manhunt is conducted by the area police department. Depending on what the suspect has done, several different agencies might take over jurisdiction. For instance, we'll talk about a manhunt that took place for a "mountain man" charged with pretty minimal misdemeanors and break-ins. That years-long search was conducted by the local sheriff's department. Oppositely, the Boston Marathon bombings were an all-hands on deck affair, involving everyone from surrounding police departments to the FBI -- thousands of officers from dozens of agencies [source: The Boston Globe]. An international case like bin Laden was led by the CIA but included collaboration among many federal and international agencies. Most agencies are very aware that such communication and collaboration is essential to a search.

A Little Technological Assistance

Agencies employ all sorts of technologies to aid manhunts, ranging from simple street cameras that can capture action on a city block to complicated facial recognition software that takes those pictures and tries to identify faces in a criminal database. (We'll see how that doesn't always work in a later section.) Things like armored trucks might also be used, especially if the suspect (like the one captured in the Boston bombings) might be carrying explosives. Many criticize police departments for purchasing the hulking machines (from about $250,000 and up) in low-threat areas (like smaller towns), but they were used during the Boston manhunt and the 2012 Newtown shooting.

As we saw in Boston, air units (helicopters) with heat sensors can also be a part of a manhunt. In addition, a forward-looking infrared device (or FLIR) detected the infrared energy from the suspect under a tarp-covered boat and allowed cops to make an arrest.

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Bigger Manhunts

Now that we have an idea how law enforcement manhunts work on a mostly domestic scale, let's take a look at how gigantic, international manhunts play out. Here's one unsurprising difference: There can be a lot more collateral damage.

This is not to say that people aren't injured in smaller-scale manhunts. In the case of Christopher Dorner, who killed four people and wounded three others in 2013 in retaliation for what he saw as his wrongful dismissal from the Los Angeles Police Department, the subsequent six-day manhunt and standoff resulted in two civilian casualties. Both occurred when police mistakenly fired on a vehicle similar to Dorner's.

But when we're talking massive manhunts, the stakes are raised even higher. In the case of Osama bin Laden, President Obama ordered broader drone attacks by the CIA in Pakistan in order to both flush out enemy combatants and weaken the organizational structure that was keeping bin Laden hidden. And keep in mind that -- despite what you might see in dramas like "Zero Dark Thirty" or "Homeland" -- there were a lot of CIA officers doing very tedious work to simply piece together attacks, transactions and communications to identify al-Qaida as an organization in the first place. By teaming with the United States military forces, they were able to start targeting specific individuals.

In long-term manhunts, surveillance often helps to home in on where a suspect lies. And that surveillance is no stakeout with binoculars and doughnuts. Consider that when the government was collecting evidence that bin Laden was hiding in the Abbottabad compound where he was found, a CIA doctor conducted an "immunization drive" in the area, hoping to collect DNA samples from bin Laden children to confirm his presence in the area.

When it comes to long manhunts over a changing landscape, global criminals don't have a monopoly. Consider someone like Troy Knapp, a "mountain man" (and ex-con) who spent six years hiding from authorities in the mountains and forests of southern Utah, breaking into cabins for supplies and living off the land. Captured in 2013, authorities had used the usual tricks for a manhunt in the mountains: mobile command posts, officers on horseback and all-terrain vehicles to navigate terrain. But despite GPS and all the fancy trappings of a 21st-century police unit, Knapp was only caught when a group of suspicious hikers came upon him in the woods. Within three days, police had used helicopter units to locate the loner and surround him in the mountains. He's charged with a string of burglaries and misdemeanors.

The kind of outlaw-manhunt that takes place in the woods is not a thing of the past, obviously. But with the advent of social media and multiple technology platforms designed to keep everyone on the information grid at all times, how has a manhunt changed?

Reddit So Wrong?

Researchers have conducted a study where teams were given a single mugshot for a group of "suspects" (located internationally). The teams were asked to use social media to suss out their identities. If folks used targeted tools (not random or indiscriminate contacts), they were able to find more success in the "hunt," perhaps showing that there is (limited) wisdom in large groups [source: Ball].

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The "New" Manhunt

For a lot of folks, the Boston Marathon bombing suspect search gave us our first look at how technology and social media changed the process of a manhunt. Not only was the search extensive, it also was available for us to digest in several platforms. Many people around the world found themselves in a self-imposed lockdown, watching real-time updates from friends on Facebook or checking tweets updating the search on their phone at work.

Increasingly, police agencies and services are turning to social media like Twitter or Facebook to apprehend criminals. It makes sense, of course: If you have a picture or description of a suspect, it's smart to get it out to a wide audience and hope that the tips roll in. Tips in several U.S. cities can also be texted anonymously to the police.

The Boston bombings provided another huge game-changer in how manhunts work: crowdsourcing the manhunt. The most sensational story about crowdsourcing came when commenters on social news Web site Reddit began combing through images around the time of the bombings to unofficially ID "suspects." The theories, according to a law enforcement official, were not correct and "complicated" the official investigation [source: Montgomery, Horowitz, Fisher]. In part, official images of the suspects were released to mitigate some of the inaccurate accusations.

As with the Boston bombings, police will occasionally release images or salient details during a manhunt not just to disseminate facts to the public but to provoke the suspects. It worked in the Boston case, as the two suspects were forced on the run.

And although the Boston incident ended with a suspect in custody, it doesn't mean that technology was purely useful to the investigation. An FBI agent had to watch bombing footage 400 times to construct a decent narrative -- the facial recognition software that would've picked up the two suspects (who do have pictures in official databases) didn't work [source: Montgomery, Horowitz, Fisher]. Turns out, there were several good old-fashioned manhunt procedures that aided in the apprehension of the suspect, coming down to one of the very first leads: a victim who woke up from his surgical amputation, requested a pen and paper, and described the person he saw drop a black backpack and walk away shortly before the blast.

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Lots More Information

Author's Note: How Manhunts Work

Let's be honest: I was hoping that manhunts were a by-the-book, step-by-step procedural that every officer memorized for a test at the police academy. And in some ways, they are: perimeters must be secured, information must be disseminated to the public and appropriate leads must be followed. But each of those processes is entirely tailored to the situation at hand. It's what makes manhunts so very complicated to engage in ... and so impressive when they do find success.

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Sources

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  • Baynham, Jacob. "Troy Knapp, a ghost in the backcountry." Men's Journal. May 2013. (May 2, 2013) http://www.mensjournal.com/magazine/print-view/troy-knapp-a-ghost-in-the-backcountry-20130402
  • Boston Globe Staff. "102 hours in pursuit of marathon suspects." The Boston Globe. April 28, 2013. (May 8, 2013) http://www.bostonglobe.com/metro/2013/04/28/bombreconstruct/VbSZhzHm35yR88EVmVdbDM/story.html
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  • Handelman, Ben. "Strategy is key for police forced into manhunt situations." Fox6 Milwaukee. April 19, 2013. (May 2, 2013) http://fox6now.com/2013/04/19/strategy-is-key-for-police-forced-into-manhunt-situations/
  • McFall, Michael and Stecklein, Janelle. "Troy Knapp, Utah's elusive 'Mountain Man' burglar, is arrested." The Salt Lake Tribune. April 3, 2013. (May 2, 2013) http://www.sltrib.com/sltrib/news/56094373-78/knapp-county-sanpete-burglaries.html.csp
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