A carpenter needs a hammer, a mass murderer needs what?

How is that gun control working in Mexico? The only people in Mexico with guns are the cartels. A few years ago one of my co-worker’s brother ( US citizen) was visiting relatives in Mexico. He was murdered in a restaurant when the entire place was shot up, killing everyone. There is no means of self defense in Mexico.

90 % of Mexico's weapons' of mass destruction come from the United states. We are the arms dealers of the Western hemisphere. That needs to change, or more stories such as yours, continues to happen

Mexico practically has become a lawless society where the government is nearly powerless to stop the cartels. Rising violence in some cities in America is result of voluntarily reducing the policing and punishment of crime. How soon before USA becomes Mexico?