This is a cult to be concerned about. There are as many as an estimated 2m people in Mexico that show some degree of attention to La Santa Muerte.
The parallels between this and Kali, the Indian death goddess, are a bit too close for comfort. Some of its followers were the Thuggee (”stranglers”), from perhaps the 14th to the 19th Century, known for their willingness to indiscriminately murder anyone.
http://en.wikipedia.org/wiki/Kali
http://en.wikipedia.org/wiki/Thugee
The British finally had enough of them, and effectively wiped them out, twice, before they were extinguished. This was done with the broad praise of everyone else in India.
The Thuggee were able to operate freely for so long because they looked like most everyone else. Much like La Santa Muerte followers look today.
For an invisible cult whose primary goal is murder, to operate freely in the US is asking for trouble.
The Indian cult mentioned is actually worship of a fallen angel, quite demonic, and many in that cult were very possessed. It still isn’t dead.