Tracey Grissom calls 911 after fatally shooting her ex-husband

Tracey Grissom calls 911 after she shot and killed her ex-husband, Hunter Grissom, in Northport, Alabama, on May 15, 2012. In the emotional call, she tells the 911 operator that she "couldn't take it no more." Watch "The Girl Next Door" Saturday, July 18 at 10 p.m. ET/PT on CBS.