The shooting in Newtown, Conn., last December has left families of the 26 victims, most of them children, struggling to heal in different ways.
Jeremy Richman and Jennifer Hensel are one such family. They lost their only child, 6-year-old Avielle, in the shooting. In the year since, they've responded as any parents would: Asking why such a tragedy could have happened.
But they also responded as the two scientists they are: They immediately threw themselves into trying to answer the question.