The Long Branch of the Law: Inside the National Park Service's Criminal Investigations Unit

The National Park Service's Investigative Services Branch handles crime in the park system.
The National Park Service's Investigative Services Branch handles crime in the park system.
Courtesy of the National Park Service

Jeff Sullivan watched as the man dug up the grave. It was the mid-1990s, and Sullivan was undercover, posing as a hunter at Channel Islands National Park, a cluster of rugged islands off Ventura, California. Every month or two, Sullivan crossed the water to meet up with a group that escorted tourists looking to hunt sheep and pigs. But Sullivan knew they were really plundering the graves of Native Americans, excavating cultural artifacts as well as bones for resale.

For two years, he returned time and again, seemingly eager to pursue sheep. Finally, one of the guides who considered Sullivan a friend took Sullivan and other undercover agents to a grave that he proceeded to dig up.

The man cautioned them keep quiet. He said disturbing the bones was a "lock-up offense."

It was exactly the kind of demonstration Sullivan had been hoping for. As the man speared the shovel into the dirt, Sullivan, wearing an audio recorder, was gathering evidence. The man and his associates were eventually convicted of illegally disturbing archaeological sites and graves, a violation of the Native American Graves Protection and Repatriation Act.

Sullivan, who testified in court about the case, is still on active duty as an assistant special agent in charge. He is not an FBI agent or a member of any law enforcement agency. For over 35 years, he’s worked for the Investigative Services Branch of the National Park Service, a division devoted to handling criminal activity committed on the staggeringly vast 85 million acres of federally owned land. The ISB routinely investigates animal poaching, missing persons, and homicides. And they do it with only a tiny fraction of the resources and manpower of the large law enforcement agencies.

“Most of us came into the agency thinking we’d just investigate poaching or resource crime, and we do,” Sullivan tells Mental Floss. “But the vast majority are crimes against people. Rapes, homicides, and everything in between.”

Inside the federal parks, he says, “People bring their problems with them.”


When President Ulysses S. Grant signed the Yellowstone National Park Protection Act into law in 1872, he was officially establishing the country’s first national park. Ever since, hundreds of parks, all owned and operated by the federal government, have fallen under the NPS umbrella. The job of the NPS is to preserve and protect irreplaceable environmental assets.

From the start, that’s been a challenge. While the land that makes up Yellowstone was once occupied peacefully by Native tribes, its increasing occupation by the government led to more disruptive activity. In the late 1800s, Yellowstone was ravaged by poachers, squatters, and vandals who had no regard for the ineffectual authority of the park superintendents who doubled as police. In response, the government dispatched the U.S. Army in 1886, stationing soldiers throughout the park to patrol the grounds and deal with problems. When a bison poacher got away with little more than a wrist slap, the public was outraged, and lawmakers established the National Park Protection Act, or Lacey Act, of 1894 to provide more stringent punishment for troublemakers [PDF].

ISB Special Agents need to feel comfortable working in remote locations.Courtesy of the National Park Service

While the Army was an effective deterrent against crime, soldiers were not exactly a wealth of park information for visitors. Hoping to create more uniformity in the growing park system, President Woodrow Wilson approved the National Park Service Organic Act in 1916, setting the stage for a fleet of park rangers who could both police and tend to visitors.

Eventually, even the rangers found themselves overwhelmed at times with activity in the park that required more specialized law enforcement attention. Following a riot at Stoneman Meadow in Yosemite in 1970, the Yosemite and Olympic national parks hired criminal investigation specialists to look into serious infractions on park land. Other parks followed suit.

Instead of parks hiring their own individual investigators, the NPS eventually opened the Investigative Services Branch, or ISB, which was given its formal name in 2003. But rangers like Sullivan had made the move years earlier. After starting in the Ozark National Scenic Riverways in the early 1990s, he became one of the first ISB special agents.

“I gradually worked my way into it,” Sullivan says. “After six years on patrol, I became an investigator.”

Yosemite National ParkBrandon_Nimon/iStock via Getty Images

If a serious crime happens on federal park land, the ISB typically has jurisdiction, though that can vary by location. (Some states have proprietary or concurrent rights to a crime scene, meaning they either take it over or work in tandem with the ISB or FBI. The latter two agencies can also work together.) That means a park official’s first call is typically to the rangers, who then contact the ISB, as in the case of the Theodore Roosevelt revolver that was stolen from Sagamore Hill in 1990. (It was recovered 16 years later.)

The ISB, Sullivan says, is contacted when a crime exceeds the threshold for what rangers typically handle. That means calls to address violent crimes, significant acts of theft or poaching, and missing persons. In the Pacific Field Office headquartered at Yosemite [PDF], agents recently addressed a 2017 assault with a deadly weapon and strangulation at a campground in Haleakalā National Park; vandals who smashed Devil's Hole pupfish eggs, a species among the rarest on Earth, at Death Valley National Park in 2016; and a DUI vehicular assault at Olympic National Park in 2017.

Sullivan has seen no shortage of memorable cases—like his run-in with serial killer Cary Stayner, who committed multiple murders in and around Yosemite, including the beheading of park naturalist Joie Ruth Armstrong in 1999. Sullivan saw Stayner driving near the park at the estimated time of the murder. Stayner later confessed to four killings total.

According to Sullivan, what makes the ISB different from other investigative agencies is simple. They’re not a law enforcement agency.

“We’re an agency that does law enforcement,” he says. “There’s a big difference.”

ISB Special Agents don't have the resources of major law enforcement agencies. Courtesy of the National Park Service

Unlike the FBI, the National Park Service is not a multi-tiered agency devoted to criminal investigation. The NPS’s main priority is protection of natural resources, meaning that the lone branch devoted to crime—the ISB—is a small part of the machine. There are just 33 special agents covering the entire country in four locations: the Pacific, North Central, Southwest, and Atlantic Field Offices. Each is responsible for multiple parks in multiple states. The Atlantic office alone covers 23 states.

“We expect [agents] to carry the bulk of the load and do the job,” Sullivan says. As a senior officer tasked with hiring, Sullivan says he looks for people who can work well by themselves and don’t mind the solitude that comes with operating in remote parts of the country.

Some agents come, stay for a bit, and realize it’s not a fit. “We live and work at the end of the road,” he says. “If you enjoy the social aspect, the nightlife, it’s not for you.”

Owing to the small staff, there’s no ISB forensic department. Agents rely on state or federal labs, hopefully building a rapport with local forensic analysts in the process. Because the ISB has to share resources, agents might also find themselves coming to the office and then being asked to jump on a helicopter to assist in an investigation three states away.

Olympic National Parkdene398/iStock via Getty Images

Sullivan says that there’s a kind of freedom in not having to deal with a lot of bureaucracy. Agents don’t just make arrests and hand the perp off to another department. They often see a case through to the end and into the hands of a prosecuting U.S. attorney, as Special Agent Beth Shott did when she successfully investigated the 2012 death of Toni Henthorn in Rocky Mountain National Park. Henthorn died after falling from a steep cliff, and her husband Harold had claimed it was an accident. Shott discovered Harold had pushed her. 

The price for that kind of autonomy is being forced to be selective when tackling crimes. With so few agents and so much territory to cover, the ISB only accepts cases they stand a good chance of solving, using what Sullivan calls the “solvability matrix.”

“We look at the level of crime,” he says. “Is it a felony? What victims are involved? Is there a suspect? Is there physical evidence?” Violent crimes often get the ISB’s full attention, though resource crimes—like the Native American grave-robbing case—can rise to the level of a top priority. The Pacific Field Office took on 49 new cases in 2018. Counting existing cases, the office worked a total of 117 incidents that year.


While there is no crime unique to national parks, there is one recurring type of case that all ISB agents have to cope with at some point: Missing persons, which often turn into cold cases.

Locating missing persons can prove challenging for the ISB.Courtesy of the National Park Service

According to Sullivan, 30 people have disappeared from Yosemite since 1909 without ever being found. Across the whole park system, 23 people are currently listed on the NPS website as missing. It’s an eerie statistic, and one that speaks to the vast and remote territory that makes up the landscape of the national parks.

“We deal with missing persons quite a bit,” Sullivan says. “People who have just vanished into the wilderness, there is lots of that.”

Some were last seen hiking. Others are believed to have died by suicide. Many leave a car behind, the only trace left of them.

All of Sullivan’s agents have at least one cold case assigned to them. When there’s downtime, they can pick up the thread and work on it. If tips come in from a call or the ISB’s social media presence on outlets like Twitter, the case can warm up again, but they often have to take a back seat to cases meeting the solvability matrix.

Among the most prominent of the missing is Paul Fugate, a park ranger who disappeared from Chiricahua National Monument in Arizona on January 13, 1980. After walking away from his station to hike a park trail, he was never seen again. Investigators suspected foul play was involved, but the case has yet to be resolved.

Chiricahua National MonumentPatrickPoendl/iStock via Getty Images

Sometimes a body appears with no context. “Jane Doe,” who was found in Yosemite’s Summit Meadow in 1983, was a young woman believed to be the victim of serial killer Henry Lee Lucas, though that’s never been proven. (Lucas, prone to falsely confessing to unsolved murders, died in 2001.)

Not all such cases come to unhappy ends. In January 2020, visitor Martin Edward O’Connor was located at Grand Canyon National Park after being missing for nearly two weeks.

Sullivan tries to resolve cases like this one as best he can. With a small staff and the same number of hours in the day as anyone else, it can be difficult. The ISB is often unheralded, with Sullivan hearing a repeated joke about agents “investigating pinecones.” That could change if the ABC television network moves forward with a proposed series about the agency, set to be produced by Kevin Costner.

Regardless, agents will still be policing a serious expanse of public land. “Yosemite gets 5 million visitors a year,” he says. “That’s 15,000 to 20,000 people a day. We have the same problems as any population the same size. We’re here to deal with it.”

14 Retro Gifts for Millennials

Ravi Palwe, Unsplash
Ravi Palwe, Unsplash

Millennials were born between 1981 and 1996, which means the pop culture they grew up with is officially retro. No matter what generation you belong to, consider these gifts when shopping for the Millennials in your life this holiday season.

1. Reptar Funko Pop!; $29


This vinyl Reptar figurine from Funko is as cool as anything you’d find in the rugrats’ toy box. The monster dinosaur has been redesigned in classic Pop! style, making it a perfect desk or shelf accessory for the grown-up Nickelodeon fan. It also glows in the dark, which should appeal to anyone’s inner child.

Buy it: Amazon

2. Dragon Ball Z Slippers; $20

Hot Topic

You don’t need to change out of your pajamas to feel like a Super Saiyan. These slippers are emblazoned with the same kanji Goku wears on his gi in Dragon Ball Z: one for training under King Kai and one for training with Master Roshi. And with a soft sherpa lining, the footwear feels as good as it looks.

Buy it: Hot Topic

3. The Pokémon Cookbook; $15

Hop Topic

What do you eat after a long day of training and catching Pokémon? Any dish in The Pokémon Cookbook is a great option. This book features more than 35 recipes inspired by creatures from the Pokémon franchise, including Poké Ball sushi rolls and mashed Meowth potatoes.

Buy it: Hot Topic

4. Lisa Frank Activity Book; $5

Urban Outfitters

Millennials will never be too old for Lisa Frank, especially when the artist’s playful designs come in a relaxing activity book. Watercolor brings the rainbow characters in this collection to life. Just gather some painting supplies and put on a podcast for a relaxing, nostalgia-fueled afternoon.

Buy it: Urban Outfitters

5. Shoebox Tape Recorder with USB; $28


The days of recording mix tapes don’t have to be over. This device looks and functions just like tape recorders from the pre-smartphone era. And with a USB port as well as a line-in jack and built-in mic, users can easily import their digital music collection onto retro cassette tapes.

Buy it: Amazon

6. Days of the Week Scrunchie Set; $12

Urban Outfitters

Millennials can be upset that a trend from their youth is old enough to be cool again, or they can embrace it. This scrunchie set is for anyone happy to see the return of the hair accessory. The soft knit ponytail holders come in a set of five—one for each day of the school (or work) week.

Buy it: Urban Outfitters

7. D&D Graphic T-shirt; $38-$48

80s Tees

The perfect gift for the Dungeon Master in your life, this graphic tee is modeled after the cover of the classic Dungeons & Dragons rule book. It’s available in sizes small through 3XL.

Buy it: 80s Tees

8. Chuck E. Cheese T-shirt; $36-$58

80s Tees

Few Millennials survived childhood without experiencing at least one birthday party at Chuck E. Cheese. This retro T-shirt sports the brand’s original name: Chuck E. Cheese’s Pizza Time Theatre. It may be the next-best gift for a Chuck E. Cheese fan behind a decommissioned animatronic.

Buy it: 80s Tees

9. The Nightmare Before Christmas Picnic Blanket Bag; $40

Shop Disney

Fans of Tim Burton’s The Nightmare Before Christmas will recognize the iconic scene on the front of this messenger bag. Unfold it and the bag becomes a blanket fit for a moonlit picnic among the pumpkins. The bottom side is waterproof and the top layer is made of soft fleece.

Buy it: Shop Disney

10. Toy Story Alien Socks; $15

Shop Disney

You don’t need to be skilled at the claw machine to take home a pair of these socks. Decorated with the aliens from Toy Story, they’re made from soft-knit fabric and are big enough to fit adult feet.

Buy it: Shop Disney

11. Goosebumps Board Game; $24


Fans that read every book in R.L. Stine’s series growing up can now play the Goosebumps board game. In this game, based on the Goosebumps movie, players take on the role of their favorite monster from the series and race to the typewriter at the end of the trail of manuscripts.

Buy it: Amazon

12. Tamagotchi Mini; $19


If you know someone who killed their Tamagotchi in the '90s, give them another chance to show off their digital pet-care skills. This Tamagotchi is a smaller, simplified version of the original game. It doubles as a keychain, so owners have no excuse to forget to feed their pet.

Buy it: Amazon

13. SNES Classic; $275


The SNES Classic is much easier to find now than when it first came out, and it's still just as entertaining for retro video game fans. This mini console comes preloaded with 21 Nintendo games, including Super Mario Kart and Street Fighter II.

Buy it: Amazon

14. Planters Cheez Balls; $24


Planters revived its Cheez Balls in 2018 after pulling them from shelves nearly a decade earlier. To Millennials unaware of that fact, this gift could be their dream come true. The throwback snack even comes in the classic canister fans remember.

Buy it: Amazon

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The Time Larry David Saved a Man from the Death Penalty


In 2003, 24-year-old machinist Juan Catalan faced the death penalty for allegedly shooting a key witness in a murder case. Catalan told police that he couldn’t have committed the crime, as he was at a Los Angeles Dodgers game at the time. He had the ticket stubs and everything to prove it.

When police didn’t buy his alibi, Catalan contacted the Dodgers, who pointed him to an unlikely hero: misanthropic comedian Larry David. On the day in question, David had been filming an episode of Curb Your Enthusiasm at Dodger Stadium. It was a long shot, as there were 56,000 people at the game that day, but maybe Catalan could be seen in the background. So his attorney started watching the outtakes ... and found the evidence he needed. In fact, it took just 20 minutes to find shots of Catalan and his daughter chowing down on ballpark dogs while watching from the stands.

Thanks to the footage, Catalan walked free after five months behind bars. And Larry David found one more thing to be self-deprecating about. “I tell people that I’ve done one decent thing in my life, albeit inadvertently,” David joked.

In 2017, Netflix released a short documentay, Long Shot, about the incident.