Kevin McAleenan: CBP port director was in Walmart during El Paso shooting

Mass shootings in 2019 are on track to surpass the total from 2018. The Gun Violence Archive counts more than 250 mass shootings, defined as any incident in which four or more people are shot, not including the gunman, so far this year in America. Acting Secretary of Homeland Security Kevin McAleenan joins "CBS This Morning" to discuss the latest shootings.