If Richard Trenton Chase experienced erectile dysfunction, then how was he ready to interact in necrophilia?

Question by Casey: If Richard Trenton Chase had erectile dysfunction, then how was he capable to have interaction in necrophilia?
Reader’s discretion is encouraged.*
Richard Trenton Chase was a crazed serial killer recognized as the Vampire of Sacramento in the late 70′s. It is said that he experienced erectile dysfunction because of to psychological troubles. When he killed his two woman victims, nonetheless, he engaged in necrophilia with their corpses, and semen was identified in the two of their bodies. So, how is this possible if he experienced erectile dysfunction?

Ideal reply:

Answer by borbor
It was situational. He could only be aroused by corpses.

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