After 18-year-old David Ludwig allegedly shot and killed his girlfriend's parents and fled with her, Pennsylvania detectives collected evidence, dusted for fingerprints and then went hunting for more clues in a surprisingly public, crowded place.

That place was cyberspace. Population: 1 billion and counting.

More specifically, police tapped into the Web logs or online personal journals of the double-murder suspect and his 14-year-old girlfriend, Kara Beth Borden. Each kept two blogs.,2933,177059,00.html