Are mass shootings a contagion?
The mass shootings in Texas and Ohio add to the country’s troubling statistics on gun violence. There have been at least 255 mass shootings this year that killed 273 people and injured more than a thousand others. NYPD deputy commissioner John Miller testified before Congress in 2016 about law enforcement support for new gun laws. He joined "CBS This Morning" to talk about law enforcement's assessments of the recent massacres.