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 …