Would it be fair to say that such people are probably psychopathic in nature?
All of them you mean? The inefficient hiders, the efficient hiders and the non hiders? Are all murderers psychopathic? Some think they may all have some sort of disorder, but then where do you place the 'normal' marker?;
"Murderers seem to have no appreciation of boundaries," Sharp explains. "And it shows up in all aspects of their lives. Most criminals I deal with are very narcissistic. They're blame-shifters, manipulative, and can't feel anyone else's pain but their own. A consistent hallmark, in fact, particularly of killers, is this extreme narcissism." Sharp points to the book People of the Lie, by the late M. Scott Peck, as a good description of a killer's personality disorder.
"These people are always the victim, it's always someone else's fault, they have no sense of other people's boundaries, and they really can't see how twisted that view is," she says. "It's a disorder."
http://www.theatlantic.com/national/archive/2010/12/are-all-murderers-mentally-ill/67295/most psychologists would say that all of us sit somewhere on the spectrum of traits included in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). A person who is classified as "mentally ill" simply sits at a much more extreme point along that spectrum.
http://www.theatlantic.com/national/archive/2010/12/are-all-murderers-mentally-ill/67295/