Here's why I think that there are few, if any more victims, among the people seen in the Alcala photo collection:
Alcala's crimes are sexual homicides, which, over a long enough period of time tend to develop a signature, a pattern based on fantasy, indicating they were committed by the same person. The signature Alcala seemed to finally develop was a meticulous posing of his victims' bodies.
Generally, investigators will be able to link subsequent victims to the same killer through that pattern or similar characteristics. If detectives supply these signature crime-scene elements to the FBI 's Violent Criminal Apprehension Program, which compares cases from all over the country, there should be matches being made. Evidently, so far that's not the case.
What about DNA? Most states, even before the Alcala photos came to light, have been combing their old murder cases, looking for DNA evidence linked to him. If nothing is found at the state level it gets forwarded to the national DNA data bank - or CODIS -- also managed by the FBI.
If you rape someone in Maine, leave DNA and then go to Florida and do the same thing, if everything runs right -- and most times it does -- they'll be matched. So if Alcala has other victims, so far they're not surfacing through DNA matches - even though that is how four homicides in California, besides 12-year-old Robin Samsoe, were also attributed to him. And consider that it was his MO to leave victims in a way where his DNA could be recovered.
Family members tend to cling to hope longer than anyone else, sometimes longer than they logically should.
I worked bank robberies for twenty years in Detroit and we would get some terrible quality surveillance photos, but when a cooperative family member was shown a picture, they would immediately identify the bank robber. In the Alcala case, the photos released are extremely clear, so if a family member can't make a confident identification, chances are the person in the photo is not the individual they're looking for.
Finally, some of the women in the photos have already come forward. Couple that with the fact that none of Alcala's known or suspected victims are among the photos found, and it would indicate to me that the pictures are not souvenirs of crimes past. I am also skeptical of the high numbers of potential victims being thrown around. When I was working the Green River murders in Washington State, the killer hadn't hit in over two years, and even though his victims were spread across a considerable distance, we pretty much had identified all 70 or so of them fifteen years before he was caught. It has been my experience that most serial killers, once caught, are closely vetted for links to unsolved cases.
For all the above reasons, I don't expect family members to find many answers in the Alcala photos. I just hope I'm wrong.
About the Author
Paul Lindsay was a Marine Corps infantry officer in Vietnam. He joined the FBI in 1972, serving 20 years with the Bureau in Detroit. He specialized in tracking down serial killers, including the Highland Park Strangler. He also worked the Green River murders case in Seattle. In 1993, Lindsay became the only agent to write a book while still active with the FBI. Threatened with suspension, he got into more trouble for criticizing his boss in a magazine article. He retired from the Bureau that same year. Lindsay has written seven novels, most recently The Bricklayer, under the pseudonym Noah Boyd. When he's not writing, he works on cold cases.