Janet Walsh murder: Will new clue solve 1979 cold case?

This story originally aired on May 16, 2015. It was updated on Dec. 31, 2016. Brittany Smith, a prosecutor in Beaver County, Pennsylvania, hadn't even been born when 23-year-old Janet Walsh last carried her purse on the final night of her life, Sept. 1, 1979. "This is Janet's purse. This would've been the purse she used the night she went out from August 31st 1979, into the early morning hours of September 1st, 1979," Smith said, showing "48 Hours" correspondent Peter Van Sant the bag's contents. Janet's pocketbook was documented and placed into evidence, where it would remain for 34 years. The items inside were preserved, as they were that summer. "...mints, gum, makeup, brush, keys. Those types of things are in every woman's purse," she said. "It definitely makes you feel as if there's a connection to her." And Smith learned Janet was firmly connected to the tiny town of Monaca, about 30 miles outside Pittsburgh, Pennsylvania. "Janet moved next door to us when she was either 2 or 3 years old. And we became best friends. She had a couple brothers. I had brothers, so she was like my little sister," best friend Sue Niedergal said. "This is the house that I grew up in, and this is the house that Janet grew up in," Niedergal pointed out as she and Van Sant stood outside the homes. …