On this particular Saturday at the beginning of May, Sherry left her house earlier than usual to make the two hour drive to Eric's apartment. The weather report had said it was going to be unseasonably warm, which translated to hot and sticky for the Florida university town where her only son was now living. She wanted to get there before the more intense heat of the noon hour took hold.

This was her son's second year, but his first living in his own apartment. Except for holidays when Eric went back home to stay with her, Sherry had driven to see him every weekend since the start of the...