But proving what these dogs know isn't easy.
"If only Buster could talk," quips Paul Dostie, as he works his black Labrador through a wide patch of scraggly brush, about 50 miles east of Yosemite National Park.
In his younger days, Buster would lie down on a spot like this to indicate an "alert," and bark. But having lost a leg to cancer, the 12-year-old canine now prefers to poke his nose in the direction of a particular spot in the dirt, or at a rock, or whatever has set off his nose. In all, Dostie says that Buster's alerts have aided in the recovery of the remains of about 200 people.
As a reward, Dostie tosses Buster a toy. "Good boy," he says.
To the untrained eye, it might seem that Buster is simply barking for that toy.
But Dostie and others who've seen Buster work say they have little doubt that the dog's nose is to be trusted.
"Seeing is believing," says Mark Noah, the founder of History Flight, a non-profit foundation whose mission includes finding the tens of thousands of fallen American veterans whose bodies were never recovered.
Buster and Dostie, working with a team of volunteers and paid staff members who also use ground-penetrating radar and historic records, have helped the organization unearth the remains of missing Americans lost in World War II battles in Europe and on the south Pacific island of Tarawa.
Among others, Buster helped find Lt. Robert Fenstermacher, an Army Air Corps pilot whose plane crashed in Belgium after being shot down in 1944. Last year, his family gathered as he was laid to rest, nearly 70 years later, in Arlington National Cemetery.
History Flight searches have led to the recovery of 13,000 bones of American servicemen on Tarawa alone, most of them not yet identified, Noah says.
Other searches are often much simpler — just the handlers and dogs, walking on foot, mile after mile. That's how Deborah Palman, now a retired specialist with the Maine Warden Service and her German shepherd, Alex, found the body of a Canadian woman named Maria Tanasichuk in 2003. Police later determined she'd been shot in the head execution-style by her husband.
"My pulse must have shot up over 200," she says of the moment she realized Alex had found the body, leading to David Tanasichuk's conviction.
Local police departments have been reluctant to use the cadaver dogs for searches because their trainers are volunteers, but that's changing, with these successes and as the dogs' training has become more standardized.
When more than one dog has alerted independently in the same spot, some judges have been persuaded to allow cadaver dog evidence.
In February, for instance, cadaver dog evidence helped convict a suburban Chicago man, Aurelio Montano, of killing his wife. She disappeared in 1990, and although her body was never found, investigators got a tip, years later, and dug up a rug at a horse farm on which more than one cadaver dog alerted. They contended that Montano had wrapped the body in the rug.
Evidence tied to cadaver dogs hasn't worked in some other cases, though.
In the high-profile 2011 Florida trial of Casey Anthony — accused of killing her young daughter — more than one cadaver dog alerted on the trunk of Anthony's car. Arpad Vass, then a senior research scientist with the Oak Ridge National Lab, testified that using air samples from the trunk, he'd found high levels of chloroform, which can be found when a body breaks down. However, his science was questioned by other witnesses, and Anthony was freed.
Cadaver dogs "are an incredible investigatory tool — no question about it," says Lawrence Kobilinsky, professor and chairman of the department of sciences at the John Jay College of Criminal Justice in New York.
But in order to present the dogs' alerts as court evidence, he believes forensic experts first need to "strengthen the science" to prove what they've found.
Even in investigations, dogs alerting is often just the first step in what can be a lengthy, sometimes fruitless endeavour.
"Everybody thinks, you just dig a hole, but it's not always that obvious," says Vass, who's still developing technology to evaluate chemical markers associated with human decomposition. Often, he says, buried bodies create a "chemical plume" that runs downhill from a clandestine grave, making it difficult to find.
"Dogs," Vass says, "are just one tool in the toolbox."
Cost also is a factor.
In Plumas County, California, Buster and two other dogs have alerted on an outdoor well on separate occasions. The well is near the home where 13-year-old Mark Wilson was living when he disappeared in 1967.
Plumas County Sheriff Greg Hagwood can't be sure the boy's body is in that well. But he thinks it's worth investigating, so much so that he asked for assistance from the Federal Bureau of Investigation, which has offered a forensics team. Having been turned down by the county board, he's also trying to find a way to raise the $96,474 to excavate and restore the site.
"How can I justify not pursuing this?" Hagwood asks. "Well, you can't."
Martha Irvine can be reached at email@example.com or at http://twitter.com/irvineap