For two years investigators worked to turn Ellen’s cold case warm. Despite the fact that her killer was already sentenced to death and would never be released, despite the time and the resources and the terrible memories involved, they didn’t give up. Eventually, their painstakingly obtained evidence built a timeline of Rodney Alcala’s whereabouts, his route before and after murdering Ellen. It seemed to me like a devotional act.

Every victim deserves her own day in court, no matter what else the culprit has been arrested for, no matter how long ago the crime: this is the pure integrity of opening a cold case. There are hundreds of thousands of cold cases in the United States. Approximately 14 percent of all unsolved homicide cases and 18 percent of unsolved sexual assault cases contain forensic evidence that has not been sent to a crime lab for analysis.

One way to close more cold cases would be to enable more states to enter into national databases the DNA information of everyone they arrest, at least for violent crimes. Next month the Supreme Court will hear a case, Maryland v. King, that could open the door to this, by deeming such entries constitutional. Currently, in part because of concerns about civil liberties, about half the states, including New York, enter into national databases only the DNA of people convicted of certain crimes — a much smaller pool of potential matches. On the bright side, New York at least does appear to be investigating and solving more cold cases than ever before.

LAST year, when I heard that Rodney Alcala was actually going to be extradited to New York to face a grand jury on Ellen’s case, I remembered something a clergyman had said at the first service after 9/11: it was too overwhelming, and unfair to the victims, to think of 3,000 people dead. The best way to honor them was to think that “one person died,” three thousand times. When justice is broken down to individual victims, humanity is restored.

In a Manhattan courtroom last month, Rodney Alcala, now 69, pleaded guilty to Ellen’s and Cornelia Crilley’s murders. After 35 and 41 years — much longer than the young women lived — he pleaded out, just like that. It was the first time in his long criminal history that he had ever confessed to a killing. The collapse of his resistance seemed taunting to all of us: Sure I killed them. What took you guys so long?

On Monday I attended his sentencing. At one point, the judge broke down, saying she had never had before her a case with such brutality and hoped she would never again. The sentence for the two murders was, of course, symbolic — a concurrent 25 years to life. The important punishment will take place in San Quentin when Rodney Alcala is finally executed — if he ever is.