Ritual killings perpetrated by individuals or small groups within a society that denounces them as simple murder are difficult to classify as either "human sacrifice" or mere pathological homicide because they lack the societal integration of sacrifice proper. The instances closest to "ritual killing" in the criminal history of modern society would be pathological serial killers such as the Zodiac Killer, and mass suicides with doomsday cult background, such as the Peoples Temple, Movement for the Restoration of the Ten Commandments of God, Order of the Solar Temple or Heaven's Gate incidents.[according to whom?] Other examples include the "Matamoros killings" attributed to Mexican cult leader Adolfo Constanzo and the "Superior Universal Alignment" killings in 1990s Brazil.[161]