FBI officers escort Cesar Sayoc to a waiting SUV after his arrest in Miramar, Florida, on October 26.WSVN Ch. 7 via Reuters

The man law enforcement believes briefly terrorized the country with a series of mail bombs appeared in court on Thursday, pleading not guilty to a 30-count indictment including charges of mailing weapons of mass destruction. What he’s accused of was perhaps the largest attempted mass political assassination through the mail since anarchists mailed more than 30 bombs to public figures in 1919.

What it wasn’t, however, was sophisticated. None of the bombs actually went off; more than one were incorrectly addressed; the packages were nearly identical, with the word “Florida” conspicuously misspelled as “Florids” on all of them. The Justice Department alleges that Cesar Sayoc’s fingerprints were on two of the envelopes. Within five days, he was in custody.

It was remarkably quick work for a sprawling investigation involving 16 suspicious packages mailed to four states—especially in comparison to the hunt for the United States’ most famous serial mail bomber. By the time Ted Kaczynski, the so-called Unabomber, was convicted in 1998, his package explosives had injured 23 people and killed three over nearly two decades. But Sayoc’s capture is more the rule, and the long hunt for Kaczynski the exception.

The Sayoc case doesn’t just highlight the difficulty of sending explosives through the mail without getting caught. It also shows the range of tools, from the basic to the technologically advanced, available to law enforcement in chasing a suspect like him. Some of those methods have improved significantly since the Kaczynski era. But Kaczynski himself was unusually sophisticated in concealing his tracks.

“We’ve been fortunate that mail bombs and mail packages involving these kinds of crimes are one of the easiest to solve,” said Terry Turchie, who headed the FBI task force that finally caught Kaczynski. Most such cases are minor, he said, and involve threats or devices, like Sayoc’s, that don’t work.

Even when they do work, Turchie said, mail bombs distribute pieces of forensic evidence, sometimes buried under charred furniture and piles of paper. Nails, pieces of pipe, glue residue, explosive material, batteries, maybe a detonator—all offer clues. Often, these clues can open a trail back to stores where the components were purchased—for instance, a specific batch of batteries being carried at a specific store—and from there to clerks who may recall details about who made similar purchases.

Then there’s the setup of the postal service itself, which has a limited number of distribution centers in each major metropolitan area, as well as its own inspection service, which investigates possible crimes using the mail system. Several of the bombs Sayoc allegedly sent, according to the criminal complaint, were processed through a single distribution center in Opa-Locka, Florida, which helped investigators narrow the search for a suspect to the southern part of the state.

There’s also the progress of investigative technology, including the proliferation of security cameras and the increasing sophistication of DNA analysis since the Kaczynski bombings. During the Unabomber investigation, Turchie said, there were not typically cameras outside of post offices, and certainly not ones that could run for 24 hours at a time.

It was the presence of such security cameras that helped solve another recent serial-bombing case, in Austin, Texas, this year, when cameras captured the suspect’s car leaving a FedEx outlet after a suspicious package had been dropped off there.

Kaczynski may have benefited from the fact that there were fewer tools available to law enforcement in the 1980s and 1990s, when he was conducting his attacks. But he was also nefariously adept at thwarting the forensic analysts on his trail. In order to remove his fingerprints, he carefully polished his bombs and sanded the wooden boxes he placed them in. He was known among some investigators as the “junkyard bomber” for his habit of fashioning bombs out of parts found in landfills rather than purchasing them in stores, the better to avoid leaving clues. Turchie recalled that more than one of Kaczynski’s bombs had avocado-colored nails—leftovers from the interior-decorating “avocado craze” of the 1960s and 1970s.

He also employed misdirection, wearing different disguises and dropping off his packages in varying locations. The one sketch of him, based on an eyewitness sighting of a man planting a device in a parking lot that later exploded, depicts a man in a hoodie and aviator glasses that obscure much of his face.

At one point, according to Steve Lapham, who was one of three prosecutors on Kaczynski’s case, the Unabomber planted someone else’s hair on one of his bombs to throw off the FBI’s then-primitive DNA analysis. He had found it, Lapham said, in a bathroom in Missoula, Montana, roughly 80 miles from the cabin outside Lincoln, Montana, where he was eventually caught.  

But even Kaczynski, who became a media celebrity known as the “mad genius” for his high IQ and mathematics Ph.D., slipped up eventually.

What helped sink him was in fact his obsessive precision—specifically, his usage of the phrase “eat your cake and have it, too.”

The idiom about trade-offs is better known in reverse: “You can’t have your cake and eat it, too.” But the original formulation puts the eating first, which makes more logical sense. You retain the option to eat the cake if you have it; the option to have the cake disappears once you eat it.

Kaczynski, unusually, stuck with the original. When it appeared in a 35,000-word manifesto he had insisted, on pain of further bombings, be published in The New York Times and The Washington Post, it was as if he had left a fingerprint. Along with other clues of philosophy and syntax in the anti-technology manifesto, the phrase helped persuade his brother David to contact the FBI in February of 1996. By April, Ted was in custody.

As for the pipe bombs sent to major political figures this fall, it was alarming that purported package bombs could be shipped to so many places with such seeming ease. Even though none of the bombs succeeded in hurting or killing anyone, they did sow widespread fear and anxiety. Assembling explosives like those doesn’t require a mad genius hiding in the woods; it’s allegedly within the capabilities of a man like Sayoc, who lived out of his van and tweeted conspiracy theories about George Soros. Instructions are freely available on the internet, and component parts can be found in stores.

But it has also grown easier over time to apprehend the people who seek to wield these weapons. Two decades after the Unabomber case, the complex systems that connect the United States remain vulnerable. The lesson of the Sayoc case, though, is less about a severe threat than about a system that worked.

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