In 1997, two women from Florida were victims of sexual assault and robbery. One year later, the police developed a suspect. Plain-clothed police officers monitored the suspect for months looking for clues that would build their case. During surveillance, the officers saw the suspect spit on the street. One of the officers grabbed a napkin and collected the spittle. The saliva, which contained cells, provided enough DNA evidence to charge the man with the two attacks.

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