How many times does this have to be explained to you bigpaul?these Mormons that were killed didn't move there in the 1870's they moved now.
The Mormon colony at La Mora was started in the 1870s so that the Mormons could practice polygamy outside the jurisdiction of U.S. laws. Polygamy is still illegal in the U.S. and has been all along, so at no time in the last 140 years were they able to get married to multiple wives in the U.S. - They would have been arrested. They have to have permanent residence in Mexico. La Mora has been their home for over 140 years.