Accurate figures are hard to come by, but the number of cemeteries in the United States has been estimated at upward of 100,000. As the demand to create digital cemetery maps inevitably increases, so will the need to locate unmarked or forgotten graves. Since many cemeteries have been around for centuries and often have incomplete records, locating graves that are unaccounted for is not an easy task.
That's where Bob Perry comes in. Perry uses ground-penetrating radar (GPR) to locate unmarked vaults, graves, and sometimes even unknown mass-burial sites. His company logo is a skull and crossbones with the words "Bone Finder" above it and "Tracking the Dead" below. Bob's equipment was described in a 2013 Washington Post article as "a heavy duty baby stroller hooked to ground-penetrating radar." But don't be fooled by its unassuming appearance: GPR devices cost tens of thousands of dollars and only a handful of manufacturers produce them. Bob scans each property on foot by rolling the GPR over acres of land for days or weeks at a time. Since 2000, he's located more than 30,000 unmarked burial sites while working with more than 500 cemeteries across the country.
The winter is Bob's offseason, so he recently sat down with me over Skype and told me what it's like to roam cemeteries accompanied only by his giant GPR.
VICE: How long has GPR technology been around?
Bob Perry: My first experience was back in Vietnam. One time we stopped in this Korean outpost, and I could see these guys pulling around this box on the ground. Of course, I had no idea what it was. They were all in civilian clothes, and it turned out to be ground-penetrating radar. Technically, GPR was invented during the Vietnam conflict.
They were using it to find bodies or graves?
No, they were using it to find enemy cells. In Vietnam, you'd have a sniper come up out of the ground and fire at you and then come up 40 feet, 50 feet away because they had a tunnel system beneath the ground. That's how they fought the war, and that's what GPR was invented for—so it could scan the ground and find these tunnels.
When did you start using GPR to locate unmarked graves?
My original business is cemetery mapping. When I first started, one of my customers wanted to know if I could probe the ground because they had a burial they had to put in and they didn't know if anyone [else] was buried there. So I [thought] that might be a good opportunity to take a look at this new equipment that's out there, which I didn't realize I had experienced years before. So I invested in the equipment. It turned out that I was the only one doing it, so I decided to make it my focus. I also do GPS mapping when I'm on site at the cemeteries. That was probably around 2000.
Can you briefly explain what ground penetrating radar is and how it works?
When the TV portrays someone scanning on the ground, they show up with this computer image of an outline of a person lying on the ground like how they are at movie crime scenes. That's not the situation. What you're looking at is hyperbolas in the ground—I call it an upside-down smiley face. The radar is measuring soil disturbance. For example, if it's flattened off, you can tell it's a vault. You can even measure the width of the walls on the vault. I have a six-point process that I go through on every burial to determine if it is in fact a human grave. I refer to it as a high probability. Unless you actually dig it, you're not gonna know. A lot of the sites I work on they do excavate the areas. So my accuracy rate is pretty good.
So the value you bring is basically to tell people where to dig. I imagine digging is time-consuming and people want to avoid doing it unnecessarily.
Exactly. And sometimes you can't find anything. I got areas at old cemeteries that I can't find anything no matter how much I scan.
Is part of the value also finding empty space that cemeteries can use for new arrivals?
Yes. A lot of the time when people move into a cemetery and they see an area that has no headstones, they automatically think it's available for burials—and it's not. Once, I located about 200 buried headstones. Around New England, they have a lot of wolf stones in the cemeteries. A wolf stone is a stone that lays flat on the ground—basically, it prevents animals and wolves from digging up the carcass.
Do you find remains that were weren't buried in graves?
I did find two mass-burial sites. I discovered them by accident. I got a call by the diocese of Savannah to scan the property just to find an urn that was in the ground. During that process they wanted me to take a look at this old Civil War site. In the meantime, when I was scanning the area I did find a mass burial site. Back in the 1800s there was a yellow fever epidemic that hit the city of Savannah. There were 800 people who perished. A lot of those people were in fact buried in the cemetery, but they buried them in a group. So I found two actual mass-burial sites.
Is this a common thing?
I come across mass burial sites all the time. It sounds unique, but you'd be surprised how many times back then they used to bury people all together in a grave. It looks like a bunch of scrambled eggs when you're looking at the radar.
Are there places where outside factors make it harder for the radar to function smoothly?
Washington, DC, is a very unique environment. You've got radio waves all over the place. I can't go ten feet without needing to recalibrate the equipment. Meaning you got to shut it off and turn it back on. Radar is affected by all sorts of elements. You've got Obama flying around in the helicopters, and it's funny: When he goes by, everything goes dead. The machine just flatlines. You've got sirens. Cell phones will actually affect the radar. Compared with working in Georgia, for example, when I'm out in a rural area and I haven't seen anyone for three days, the GPRing is beautiful.
Over the years, have you counted how many unmarked graves you've found?
I'm in the 30,000 range. I've worked in well over 500 cemeteries across the country, so I've got quite a few cemeteries under my belt. DC's Historic Congressional Cemetery is my biggest [project] to date. I found 2,750 so far. I'm projecting maybe 4,500 unmarked graves there [upon completion].
What has been your favorite project so far?
My favorite project is the one I did in Sudbury, Massachusetts. That's an actual Revolutionary War cemetery. The last burial they had there was 1840, I think. Back about 1910, 1920, they put in a stone wall around the cemetery portion of it. Well, after I scanned the whole area I started scanning along the wall, then on the other side, on the walkways, and even where they park their cars, and I was finding burials out there too. I let 'em know about it in the report. It's their information. What they want to do with it is just totally up to them. They don't want to open up a can of worms and move the whole parking lot because there's burials out there.
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