I sincerely hope you are right as this implies that not only is the killer local, but that others have direct knowledge of the circumstances behind the murders as well. This means that big breaks can still come.
Here is the name of the victim from Mississippi:
https://www.cbsnews.com/news/suspec...ssissippi-teen-jessica-chambers-burned-alive/
Objectively, I think you are 100% correct. A drug related motive in this crime does not make objective sense. But... Over reaction / Over kill drug murders often have subjective elements that drive the perpetrator's motives.
These elements can include a drug deal and: respect / disrespect issues, desires to punish a "traitor", teach a "lesson", obtain status in the criminal world etc. . Then factor in that a certain number of drug dealers are inherently violent and don't need much of either an objective or subjective reason to hurt people.
Often times, drug gangs are not like the Mafia, Yakuza, or Tongs where the criminals are led by an intelligent, objective thinking leader who had been given a lot of institutional knowledge in what allows the group to "succeed" long term. This leader then orders violence only after all risks and gains have been considered (well... usually).
Rather, small independent drug gangs can be led by idiots who are incapable of objective thinking and act impulsively with horrific violence over trivial matters.