In October 1996 an abandoned Plymouth Voyager van was discovered near the Anvil Spring Canyon in Death Valley national park, by a ranger doing routine checks. Since the use of vehicles in this area was prohibited, it was unusual to find a car out there, much less an abandoned one, which was totally unsuitable for the terrain and seemed to have flat tires and was broken down. It turned out to be a rental, with California license plates and had been rented by a family of German tourists went missing while driving through Death Valley in July. The case remained unsolved until 2009, when one hiker got curious enough to take matters into his own hands and train to obtain the skills necessary to “man track” in order to find the missing death Valley Germans.
This is link to his website, with his journal detailing the story of how he went about resolving the case.
It’s an amazing read.