1. Cutting 1 CUTTING
Behind the convenience store, in full view of a broken surveillance camera, a camping chair and a blood-stained blanket sit abandoned in the urban blight. A pool of blood cools into gel on the sidewalk, separated from the rest of civilization by two fluttering lines of yellow crime scene tape. Past the police line, brick apartments squat on and on and on.

A passerby peeks over the tape. “He got him three times in the back and once in the chest!” he shouts.

But that is almost certainly not what happened.

What did happen behind this convenience store is, at this moment and legally speaking, a mystery. According to the dispatch call, it was a “cutting,” a police department term for what would colloquially be called a stabbing. Jill, a blunt, raspy-voiced officer for the Baltimore Police Department, arrived soon after it happened. She chased the suspect across the street, where she detained him. Then she walked back to the scene, hunting for witnesses. She found only one.

Back at headquarters, crime laboratory technician Erika Harden was just beginning her ten-hour shift. The call came through around five p.m., while she was prepping her equipment. Over the radio, Harden announced that she was “10-8,” the code for in-service, then took the elevator down to the bay, a cavernous garage that acts as a staging area for the crime lab. She loaded her gear into a black, all-wheel-drive, midsize SUV marked FORENSICS, and headed into the literal sunset.

Over the millennia since the Cuneiform laws first codified rules of behavior for ancient civilizations in the Middle East, millions of people have been employed in an attempt to enforce them: Roman quaestors and Chinese prefects and Islamic muhtasibs; international tribunals and police departments equipped with military-style weaponry. Erika Harden represents the slickest, most postmodern moment in this historical procession. She is a professional crime solver who uses cutting-edge science to determine who is responsible for transgressions, so wrongdoers can be brought to justice and prevented from causing further harm. Using nothing but physical tools and logic, she travels backward through time, re-creating a crime in as much detail as a courtroom can stand.

This job has many names: crime scene investigator, evidence technician, forensic investigator, crime scene technician, crime scene analyst, and crime scene examiner among them. Technically, Harden is a Crime Laboratory Technician II, a title confusing enough that it has misled people into thinking it was a laboratory job. A more illustrative title is “criminalist.” Like a numismatist is a student and collector of coins, a criminalist is a student of criminalistics, a person who collects evidence in order to understand a crime in as much detail as possible. A criminalist should not be confused with a criminologist, which is a person who attempts to explain social deviance on a grand scale by plumbing the depths of psychology, policy, and punishment. A criminalist doesn’t worry about the why of a crime. She deals in more prosaic questions: When? How? And most important, who?

ERIKA IS TWENTY-SEVEN, BUT appears younger, with kohl-rimmed eyes, plastic-gauged earrings, and a silver nose ring. She looks more like the lead singer in a punk band than a crime lab technician, which she has been for three years, ever since graduating from Stevenson University in Owings Mills, Maryland, with her master’s degree in forensic science. She works ten hours a night, four nights a week, which sounds onerous but isn’t really. The traffic is better at night than it is during the day, and she’s used to late hours. In between school and starting at Baltimore PD, Harden worked shifts at a local bar.

Like many of her generation, Harden discovered crime scene investigation through the CBS show CSI, which catapulted the profession to fame after it premiered on October 6, 2000. Although it’s difficult to imagine after sixteen seasons and an unending series of sequels, spin-offs, and imitators, the general public knew next to nothing about criminalistics before CSI. For most of the profession’s history, crime scene investigators toiled behind-the-scenes in obscurity. People used to just fall into the job through a well-timed classified ad, the military, or friends and family who worked in law enforcement. Then came the show, which crime scene investigators in the younger age ranges almost universally claim as their first exposure to the career. For all its cheesy one-liners, CSI introduced the country to a job that rode the balance between law enforcement and hard science, where a smart nerd who lacked squeamishness could serve justice just as well as a hard-boiled detective in a fedora. It was Sherlock Holmes with Luminol. Scooby-Doo with liquid chromatography mass spectrometry.

Was that even a real job?

It was. And Erika was lucky enough to have an aunt who could tell her all about it. Harden’s aunt, Mary-Pat Whiteley, was a veteran crime scene investigator in the original mold. She started off as a fingerprint tech for the FBI, then transitioned into the lone crime scene investigator for Annapolis City, Maryland. Over Thanksgiving dinners, Harden and her aunt would discuss the intimate details of crime scene investigation until the rest of the family asked them to please shut up because they were grossing everyone out. Harden became the first person in her family to earn a college degree, then stayed on for a five-year bachelor’s-to-master’s option, becoming the first person in her family to earn a master’s degree. And here we are.

If you saw Erika Harden working in the street, like she is now, you might mistake her for a police officer. She wears black tactical pants and a long-sleeved baselayer under a black bulletproof vest marked FORENSICS. She used to wear her hair in a ponytail, but switched to a pair of dark braids twisted into a bun after she almost dragged the ponytail’s tip through some suspected blood. On her belt: a flashlight, pepper spray, keys, and a radio. No sidearm. Harden is a civilian.



Harden whips out a tablet and opens an app called CrimePad. She creates a new case, followed by a new scene, and the app automatically records the date and time. This scene is fairly straightforward: only one person has been injured; the suspect is in custody; there aren’t weapons lying around; and the combatants didn’t run for five blocks and leave haphazard trails of evidence all down the street. All Harden has to do is take notes and photos, collect evidence for analysis, and be on her way.

A tablet app for crime scene investigators may not sound as exciting as the James Bond–worthy lab gadgets featured on crime shows (we’ll get to those), but CrimePad has been a monumental advance over the technology CSIs previously used to describe scenes, which amounted to scribbling observations in spiral-bound notebooks. CrimePad organizes observations, evidence, and sketches through a series of drop-down menus and customizable screens that serve as guidelines for documentation. It creates an electronic record that assists with future reconstructions, such as for cases that don’t come to court for years. Understandably, some 250 police agencies across the country have adopted the app since it launched in 2014.

Now for the cool stuff. To collect physical evidence, Harden uses a personalized kit containing her camera, external flash, batteries, measuring devices, and envelopes.Disposable scalpels and box cutters for scraping up paint or cutting carpet. Tweezers for grabbing anything tiny. In case of an especially messy scene, she’s got personal protection equipment: gloves, hard hat, fire boots, and coveralls. There are lift cards, brushes, powder, and tapes for collecting fingerprints. Swabs for blood and DNA.

There’s more in the trunk: plastic bins loaded with paper sacks; red plastic biohazard bags; weighted and numbered yellow triangles to mark the positions of physical items on the ground; a sharps container. An arson kit contains metal paint cans inside which investigators can seal burned or fuming evidence. Every car contains a ladder, a tripod, a safety kit, and a metal detector.

For the sake of speed and efficiency, Harden doesn’t get to use the department’s coolest tools, such as the Leica C10 3D laser scanner, which creates a 360-degree, high-resolution image of a crime scene in minutes, except in the most serious situations: shootings that involve police, mass casualties, national news-type events. But the crime lab is always on the lookout for spy-caliber gadgets that they hope the department will swing enough budget to purchase. Recently they got a little DeWalt camera that can peek into a hole in a wall to search for projectiles. “It has a magnet that will pull it out for you,” Harden says.

It’s the time of the evening photographers call the magic hour, when the waning light makes headshots, wedding photos, and art prints come out color-true and crisp. Harden adds a photo element to her scene in CrimePad to note that she’s taking pictures and pulls out her department-assigned Nikon D7200 digital camera. She takes a long-range photo from the nearest large intersection, where a street sign and the convenience store’s marquee can establish an address. She steps closer for midrange shots, squats for the close-ups.

Photography is such a critical part of crime scene investigation that it morphs into a hobby for many who do the job. In addition to fulfilling required compositions—long-range, midrange, and a close-up for every major detail—crime scene investigators need to take photos that are high resolution, focused on the correct items, and free of blur. Most investigators operate their cameras at least somewhat manually, adjusting the lighting, aperture, shutter speed, and ISO setting as the situation requires. So far, Harden hasn’t gone crazy with photography, but she knows techs who do it on the side for income or fun. There’s even a photography competition at the annual meeting of the International Association for Identification (IAI), a major trade group for crime scene investigators: only some of the photos are of dead people.

Harden opens an evidence element in CrimePad and types in a description of the bloody blanket lying near the scene of the cutting, which she collects wearing nitrile gloves and places into a paper bag. She would never store suspected blood in plastic, because one of the cardinal rules of crime scene investigation is that plastic can encourage the growth of bacteria that degrade DNA, rendering it unusable for analysis. This is the science part of forensic science—knowing how to collect evidence so that it can be analyzed and deployed in court is as important as knowing what to grab at a scene. Technically you could send anyone to recover evidence—a beat cop, an untrained civilian, the detective working a case—but this specialized procedural knowledge is why a trained technician will do the best job. A criminalist is, at her most fundamental level, careful. Her carefulness creates order, and order creates answers.

Normally, Harden would next drive over to one of Baltimore’s ten or so hospitals to photograph the cutting victim’s injuries, creating a second scene for the same case in her CrimePad app. Tonight she won’t have to. Another technician on the night shift happens to be working his own call at the appropriate hospital and has offered to take Harden’s photos in her stead. The techs do this for one another constantly. In a job requiring long shifts, constant focus, and inhuman flexibility, you never know when a small favor will allow you to trade an hour of overtime for an hour of much-needed sleep.

Harden takes off for headquarters just as the fire department arrives to hose off the remainder of the blood. The restoration of individual homes or businesses after a crime is the responsibility of the owners, and private crime scene cleanup organizations offer intensive decontamination, odor removal, and cleanup services for a fee. On public property, such as this sidewalk, the fire department usually handles it themselves.

“That wasn’t as exciting of a scene as I thought it would be,” says Becca Jackson, who is in her first year as the night shift’s assistant supervisor and who has offered to drive an annoying journalist (me) around all night to watch the team work. I have never seen so much blood outside of a donation bag and make a soft oh yes, very boring indeed type sound while continuing to be surprised that police departments allow people to go on ride-alongs at all. Jackson continues, with resignation and dark amusement: “There will be more tonight.”

If that seems cold, it is only because psychological distancing is part of the job. The eight investigators on Harden’s ten-hour shift handle an average of fifteen to twenty scenes a night, collecting clues in shades from mildly unpleasant to nauseating. You can come across anything in this profession: a battered woman, a body crawling with bugs, a child pornography server. It is, perhaps, the best way to regularly come into contact with horrors that only appear to the rest of us when some awful, inconceivable event whisks away the curtain of ordinary life. As Jackson puts it: “If we have to come out, it’s not a good day.”

Thankfully, the average person rarely encounters crime scene investigators, but they are out there all the time, performing an essential service. The job sits at the intersection of forensic science and law enforcement, supporting the broader ecosystem of police work. Crime scene investigators provide intelligence that guides investigators, prosecutors, and juries on their way to confer justice. It is a job both immensely complex and inherently simple, the conceptual equivalent of the law’s personal magnifying glass.

Most of the people you’ll encounter in this book work for the Baltimore City Police Department, a team of professionals I shadowed, rode along with, and interviewed in the fall and winter of 2019–2020. Scattered throughout these pages are other experts I met or talked to along the way, at other departments, at industry conferences, and at forensics schools, as a necessary counterpoint. Although accurate numbers are difficult to track, the Bureau of Labor Statistics says there were 17,200 “forensic science technicians” as of 2019, and these workers are scattered across state and county labs, police departments, and private offices all over the country. Everywhere this job is practiced, it is practiced a little bit differently. Everywhere, it can be smelly, dangerous, and physically and emotionally punishing.

But it has its moments. At a stoplight on the way back to headquarters, a group of enterprising young black men is washing car windshields for tips. A boy who can’t be more than sixteen approaches Jackson’s driver’s-side window and uses his squeegee to draw a heart on it in soap. You don’t need me to tell you that cops are not always beloved in a city like Baltimore, a city with a deep history of racial injustice and police brutality, where the 2015 death of Freddie Gray in police custody incited days of protests and riots that presaged the national Black Lives Matter demonstrations of 2020. But the forensics vans don’t make people angry. They inspire the kind of respect people have for the fire department. Jackson and Harden wield no guns, no handcuffs, no citation forms. They carry iPads, and fingerprint kits, and really cool cameras.

They don’t come to punish; they come to solve. What is there to dislike about that?