The serial killer who inspired acclaimed mystery movie Zodiac has been unmasked by his own stepdaughter. Deborah Perez claims spectacles she snatched from Guy Ward Hendricksen's last victim will prove that he was the fiend who terrorized San Francisco, California in the late 1960s and avoided capture.

The police investigation into the Zodiac Killer murders was revisited in the 2007 film, which starred Jake Gyllenhaal and Robert Downey Jr..

Perez has kept her dreadful memories to herself for 40 years - because she witnessed at least two of her father's slayings and even helped pen several of the mocking notes he sent to police, according to the Globe.

And she reveals that, as a child, she embroidered a mask the Zodiac Killer wore on his killing sprees.

Hendricksen died in 1983 after losing his battle with cancer.

Perez, now a real estate broker, insists she never realized her late stepfather was the Zodiac Killer until the film prompted fresh interest in the case, and America's Most Wanted revisited the killings. Upon seeing a police sketch of the sick murderer, she realized it was her father.

The 47 year old's evidence could serve to clear pedophile Arthur Leigh Allen's name - San Francisco journalist Robert Graysmith, played by Gyllenhaal in Zodiac, claimed Allen was the killer in his book, which the movie was based on.

Allen died of a heart attack in 1992.

(This news article provided by World Entertainment News Network)