Authorities found Fischer dead from "numerous injuries" at her Pebble Hill Road home in Doylestown on Feb. 17, 1960. She was last seen alive by a friend the weekend prior on Feb. 13.
A Chicago native, investigators said she was self-employed as a travel agent and ran her business out of her home.
Fischer was married to "millionaire industrialist" Kermit Fischer, but authorities say they were estranged — Helen was reportedly seeking a divorce and even had pending assault charges against her husband at the time of her death, police wrote.
Kermit died on a business trip in Antwerp, Belgium in 1971, according to his New York Times obituary.
Anyone with information should call the Pennsylvania State Police at 610-861-2026 or submit a tip via Crimewatch.
Click here to follow Daily Voice Bristol and receive free news updates.