Unfortunately, gun is a sporting tool in US and not a weapon and this thinking has to be changed. Why cant the americans understand that if a knife can be a weapon which can kill, why not treat the gun which can also kill as a weapon?. Unless there is control on guns, things like this will continue in US. However, incidents such as these are rather rare on the university campuses since there, the students go to learn unlike in most Indian universities, where they carry guns to rule the universities.
