be the magic phone call. >> there was something that might lead them to the killer. the way mark had been murdered. the killer had been lying in wait. mark was shot at point blank range. execution style. all of this lead investigators to think that this could be an organized crime hit. >> rumors are sweeping the town! top of mexican drug cartels, and prison games. >> we're open to every avenue. >> nbc's channel five in dallas covered the case from the beginning. and reporter, ken, was there for it all. >> mexican drug cartels were suspected immediately because of the fact that has he had been involved in drug cases over the years. >> and investigators also suspected another group. less publicly known, but very dangerous. the aryan brotherhood of texas. a prison gang of rights supremacists. >> why was the aryan brotherhood of potential group that had done this? >> there had been some threats