Her longtime manager Brad Lemack confirmed the sad news. According to Brad, Betsy died of natural causes at a hospice care center in Connecticut, reported Ace Showbiz.
Betsy, who was born on November 1, 1926 in East Chicago, Indiana, had appeared in some films, Broadway and on TV shows for years before she took the role of Pamela Voorhees in "Friday the 13th" alongside Adrienne King, Harry Crosby, Laurie Bartram and Kevin Bacon.
She returned briefly in 1981's "Friday the 13th Part 2".
She also appeared on some TV shows like "Knot's Landing", "The Love Boat", "Newhart", "Just Shoot Me!", "TJ Hooker" and Murder, She Wrote".
Betsy is survived by her daughter Melissa Merendino.