It was a crime that shocked the country. On March 12, 2011, two young saleswomen were found brutally attacked inside a lululemon athletica retail store in Bethesda, Maryland, one of the nation's wealthiest suburbs.

Thirty-year-old Jayna Murray was dead--slashed, stabbed, and struck more than three hundred times. Investigators found blood spattered on walls, and size fourteen men's shoe prints leading away from her body.

Twenty-eight-year-old Brittany Norwood was found alive, tied up on the bathroom floor. She had lacerations, a bloody face, and ripped clothing. She told investigators that two masked men had slipped into the Bethesda lululemon store just after closing, presumably planning to rob it. She spoke of the night of terror she and her coworker had experienced. Investigators were sympathetic...but as the case went on, Brittany's story began to unravel. Why rob a business that dealt mostly in credit cards? Why was Jayna murdered but Brittany left alive? Could the petite, polite Brittany have been involved? Most chilling of all: could she have been the killer?