MSNBC Live with Alex Witt 10/03/15

45 school shootings in U.S. so far in 2015

Pia Carusone, executive director of the anti-gun violence group Americans For Responsible Solutions, joins Alex Witt to discuss the findings of a new report, which calculates that the U.S. mass shooting rate has tripled over the past three years. ... more Duration: {{video.duration.momentjs}}