What can be done to stop wave of violence?
A teenager killed nine people at a busy shopping district in Munich Friday, before turning the gun on himself. The shooting bookends a week which began with a former Marine opening fire and killing three police officers in Baton Rouge, Louisiana. Ron Hosko, a former assistant director at the FBI, joins ''CBS This Morning: Saturday' to discuss the ongoing threat in Europe and here at home and the "shared responsibility" to prevent the attacks.