It was a balmy Sunday evening in early 1999, and Dr. Kaw Bing Chua hadn't had lunch or dinner.
There wasn't time to eat. Chua was chasing a killer. And he thought maybe he had finally tracked it down.
He slid the slide under the microscope lens, turned on the scope's light and looked inside. "A chill went down my spine," Chua says. "The slide lit up bright green, like bright green lanterns."