CNN/ Chicago grad student David Gimelfarb (pictured), 28, is one of three men who disappeared in Costa Rica in 2009 and are still missing. The case of hiker Gimelfarb with Craig Snell and Michael Dixon shares some similarities. All three men left belongings behind while walking along beaches or near the coast. But there have been sightings of someone matching Gimelfarb's description. His family believes he may be suffering from amnesia or an illness.
