Investigators looking into the kidnapping and murder of DEA special agent Enrique Camarena and DEA source Alfredo Zavala faced several hurdles that threatened to derail their efforts to collect evidence in the case. These hurdles almost prevented forensics experts from determining the facts of the case and threatened to undermine the investigation of the crime. However, despite these obstacles, use of standard forensic techniques eventually enabled investigators to solve the case.

1. 1. What were the main challenges facing investigators who were collecting evidence in this case? Give specific examples of these challenges.
2. 2. Explain how investigators used reference samples to determine that the victims had been held at the residence located at 881 Lope De Vega.
3. 3. Explain how investigators used reference samples to determine that the victims' bodies had been buried and later moved to the site where they were discovered. Also explain how they used such evidence to determine the original burial place.