>> somebody came in there with a purpose. it was obvious whoever did this was going to make sure there was no living witnesses to report it to the police. >> both male victims in this case were known drug dealers. and one of them, adelbert sanchez, had family members tied to the mexican mafia. >> adelbert had family members that were incarcerated, in federal prison in texas, in florida, involved with the sale and transport of large amounts of marijuana from mexico, south texas. >> but detectives could find no connection between the mexican mafia and the murders. and despite investigators' best efforts, the trail of the killers eventually turned cold. >> there was a lot of frustration in this case, wondering, are we going to catch this person? or it's got to be this person right in front of us. >> the families wanted answers. they deserved answers.