Two of the country's most notorious survivalists -- the Hermit of North Pond in Maine, and The Mountain Man of Utah, were found and arrested in the last few weeks. And a case of a missing family, the McStay family of southern California, was effectively closed when investigators said the family appears to have gone to Mexico voluntarily.
So is it still possible to "disappear" in 2013?
"Is it more difficult? Yes," said Jim Biesterfeld, a former U.S. army counter-intelligence special agent who teaches private investigations at California State University-Fullerton Jim Biesterfeld. "Impossible? Not even."
For someone to hide away from society, he said, at least two things are essential: self-sufficiency, and desire.
"There are not that many people who want to stay hidden for that long" in solitude," Biesterfeld said. "Most people try to establish new identities."
That's why it's unusual for two cases of solitary survivalists to have been solved in such close succession.
Christopher Knight, 47, also known as The North Pond Hermit, appears to be one of those few who truly wanted to live on his own.
For 27 years, Knight avoided making a campfire for fear of drawing attention to himself. He stole what he needed to survive from campgrounds; in fact, everything he had was stolen except his eyeglasses. If there's not much reason to be found, as in Knight's case, costly police investigations are unlikely. But, eventually, Knight's thefts of food and survival supplies prompted local law enforcement to get involved.
It would take a possible federal criminal violation in addition to a disappearance, such as a fugitive or kidnapping situation, for the FBI to become involved, said FBI special agent Kathy Wright.
"The FBI requires an authorized law enforcement purpose to conduct an investigation," she said. "The mere fact that an adult disappears, is not, on its own, a violation of law."
In the end, a surveillance camera set up specifically to catch Knight triggered an alarm when he entered a campground kitchen looking for food, and Knight was arrested.
While technology -- such as thermal imaging that detects people by tracking body heat -- is helpful in pinpointing a location once a general area is mapped out, investigators haven't abandoned old-fashioned methods. In the case of Troy James Knapp, also known as The Mountain Man in Utah, it was snowshoe tracks that eventually gave him away.
Biesterfeld relies on the old adage of investigators and journalists: Keep It Simple, Stupid. Find out everything you can about the person.
"What was he like as a kid? Did he have mental health issues? Had he ever talked about it before?" Biesterfeld said. "In most cases, people crave human contact. The rare few who do not are the Maine guy and the unabomber" -- and, it appears, Utah's Mountain Man.
"He says, 'I don't hate people. I just don't like living with them,'" the Huffington Post quotes him telling Sevier County Sheriff Nathan Sheriff Curtis.
Knapp had been living off the radar since 2004. He caused more disturbances than Knight, sleeping inside other people's cabins and stealing food, camping equipment and guns. But because searchers knew his habits, they were able to discover the snowshoe tracks that led them to him.
Knapp's trial started this week; there are 29 burglary-related felony and misdemeanor charges filed against him.