Testimony begins in trial of mother charged in school shooting committed by son

A jury in Pontiac, Michigan, heard opening statements and the first witnesses today in the involuntary manslaughter trial of Jennifer Crumbley. She is accused of not doing enough to prevent her son, Ethan Crumbley, from shooting four fellow students to death at his high school with a gun given to him by his father. NBC News' Adrienne Broaddus reports.