I guess that means negligence is not an official cause of death.
The issue is not whether he died of homicide or suicide, it's that he died at all while in custody as the highest profile prisoner in that jail since el chapo. Don't search for murderers when the guilty parties are practically staring you in the face: the warden, shift supervisors, and practically every guard on duty that night. Their crime may not be homicide, but they all deserve to be royally shafted professionally, legally, and personally.
Let's see some pictures of the warden and the others so the court of public opinion can ruin their lives as, say, judge Kavanaugh was treated publicly.