Anchored by Jake Tapper, The Lead airs at 4 p.m. ET on CNN.
We've moved! Come join us at our new show page.
(CNN) - The school shooting in New Mexico is just one of the latest active shooter events that have become so common, that other examples roll off the tongue: Newtown, Navy Yard, Fort Hood, Virginia Tech.
A recent report out by the Advanced Law Enforcement Rapid Response Training center looked at more than a hundred active shooter events, which are defined as one or more persons whose primary motive is mass murder in a confined or populated area, not including gang and family-related shootings. The researchers found the number of these types of mass shootings has increased, from an average of about 5 a year prior to 2009, to 15 in 2013.
Events that led to the latest school shooting in New Mexico are not uncommon.
"Typical for school shooters in particular (is) getting their weapons from their family, going to school, and then maybe being frustrated with particular individuals at school, but taking out their frustration more randomly, more generally against the school as a whole," said J. Peter Blair, associate professor of criminal justice at Texas State University, who worked on this study.
For more of our interview with J. Peter Blair, check out the video above.