IN the wee hours of July 14, Elizabeth Roach, a 70-year-old widow, got out of bed and went to the living room of her Virginia ranch home. She sat in her favorite chair for 15 minutes, then returned to bed.

She rose again shortly after 6, went to the kitchen, plugged in the coffee pot, showered and took her weight and blood pressure. Throughout the morning, she moved back and forth between the kitchen and the living room. She opened her medicine cabinet at 12:21 and closed it at 12:22. Immediately afterward, she opened the refrigerator door for almost three minutes. At 1:36, she opened the kitchen door and went outside.