a bale of marijuana in the bottom. it is information mexican authorities have had since the very first day. sheriff, i mean, i've got to ask you, is that possible that mexico is going to find, catch and adjudicate the killers in what is a lawless part of mexico? >> i really cannot answer that, but i can tell you this. that based on their past record, i think they have somewhat of a zero solvency rate and a zero conviction rate. >> and there is one more piece of evidence. a small blood spot on the life jacket tiffany hartley wore the day she says her husband was shot. the blood is from her husband. sheriff gonzalez says the dna test confirms it. but even the dna match remains just one more piece of an unsolved puzzle.