Can anyone tell me how gun control laws reduce crime?

Woodbine - Can anyone tell me how gun control laws reduce crime? According to government statistics they actually increase crime. New Jersey, California, Illinois and New York all have some of the strictest gun control laws in the nation, yet cities in these states have the most gun crime in the country. Most mass shootings have occurred in "gun free zones." How is this possible since you can't have a gun there? Most gun crimes are committed by people who are already prohibited from having a gun. Every state where a person can carry a gun has a lower crime rate. All this per the FBI. We need more laws?