Adam Barrett, ICU nurse, shared the patient bedside with investigators searching for clues that might break the case. "It was kind of hard to hear somebody say, 'Don't wash that wound. You might wash evidence away.'" Barrett cleaned shrapnel and nails from the wounds of some victims, side by side with law enforcement investigators who wanted to examine wounds for blast patterns. The investigator's request took him aback at first. "I wasn't stopping to think, 'What could be in this wound that could give him a lead?'"