After three murders with chillingly similar scenarios occurred in Austin, Texas, police began to wonder if they were chasing a serial killer. But whomever committed the crimes left no evidence, no DNA. Cops went into a frantic investigation. The hunt for clues changed when a man testing out a new thermal imaging scope recorded the nighttime movements of a stranger the night of the first murder. As "48 Hours" correspondent Maureen Maher reports, it was evidence cops never expected - and would help them break the case.

A SHOCKING CRIME

These days in Texas, it seems like all roads lead to Austin. The sleek skyline of the Lone Star capitol---glittering. A boom town that welcomes newcomers, chasing dreams. It's a city charged with life -- an unlikely place to find tragedy as dark as the death of a dreamer, like Kathy Blair.

Read the entire CBS news show '48 Hours' transcript using the CBS link above.