In 1998, when new laws were passed, 65 murders were committed with firearms. In 2010, the latest figure available, it was almost twice as many: 122, an increase of 88 percent.

The reason, says criminology Professor James Fox from Northeastern University, is inconsistent gun laws.

“Each state, to some extent, is at the mercy of other states around them,” Fox said. “What we really need is some federal legislation that will guide all the states.”