The Outer Limits (1995)

FBI agent Jamie Perrin has investigated some pretty strange cases in her time but this one may be the strangest of all. During the last fifty years, seventeen men throughout the country were all murdered with the same gun. This gun is traced to Dr. Theresa Givens, a scientist who recently left a top-secret government agency. This discovery deepens the mystery because Givens was only five years old at the time of the first murder. The gun itself hadn't even been made. While investigating further, Perrin discovers a secret that lies behind the locked door in Dr. Givens' office and learns first-hand of the temptations and dangers of undoing the evils of the past.