Most of the subjects in the photos have never been identified, and officials worry that they might have uncovered a trophy case of additional victims of Alcala.
"We'd like to locate the women in these pictures," prosecutor Matt Murphy told the Orange County Register. "Did they simply pose for a serial killer, or did they become victims of his sadistic, murderous pattern?"
Hundreds of photos recovered during court-authorized searches of Alcala's Monterey Park home and a storage locker were released Wednesday.
Police say some of the photos show women and young girls in the nude and engaging in sex acts.
Prosecutors said Alcala, the 66-year-old amateur photographer and UCLA graduate, used his camera as a way to convince victims to trust him.
A jury on Tuesday recommended a death sentence for Alcala for five murders he committed in the seventies. Jurors took just an hour to return the death recommendation after a six-week trial in which Alcala represented himself and took the stand in his own defense.
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