Law officers from Iowa and Texas say it took thousands of hours of work to unravel the mystery behind the deaths of 11 illegal immigrants found in a rail car in Denison last October. That work led to an indictment unsealed Thursday that charges four men with conspiring to run illegal aliens into the U.S. from several Central American countries. Texas F-B-I agent Rosemary Amerena is credited with leading the effort to identify the badly decomposed bodies of the 11. Amerena says that work included traveling thousands of miles to Guatemala, Honduras, El Salvador, Nicaragua and Mexico to get D-N-A samples from relatives. The relatives were initially identified through wire transfers of money sent to pay the passage of their relatives. But she says finding them to get a sample was like finding a needle in a haystack. She agreed with that characterization, saying they’re very impoverished countries and they had to get messages through people who had telephones. In many cases it meant going door-to-door to try and find the people. She says once they identified the people they thought were relatives — getting the samples wasn’t hard. She says they were very concerned about their loss and were very agreeable to giving samples. Amerena was asked if the family members realized the danger their family was going through to try and get to the U.S. She says some were aware, and some were disappointed that their family members chose to take that route. She says a lot of them did not want to believe it was their family member, but gave samples to find out if it was the person they were looking for. Two of the four men who ran the ring out of Mexico and southern Texas are in custody, and the search is on for the other two. The each could face the death penalty if convicted in the case.