In August of 1999,  best friends Raffi Kodikian and David Coughlin set out across the United States on the adventure of a life time. David was leaving Boston Mass. on his way to California to continue his education in  the field of traffic policy analyst. They decided to stop and camp for the night at Rattlesnake Canyon in the Carlsbad Caverns National Park, not knowing that the worst days of theirs lives were ahead of them. 

Sources for this episode are:
 Murderpedia/ Raffi Kodikian
Los Angeles Times: Mercy or Murder? Doubts About a Death in the Desert by Pauline Arrillaga 
Wikipedia for dates and locations.