A serial killer who could have been stopped

Rating: 8/10 (10 November 2018)

The performances by all of the cast in "Zodiac" are very good. One can't know how well they reflect the personas of the real people they portrayed from the book and true story. But, the film gives a sense of reality in the roles of the investigating detectives and police, and of the lead character. Jake Gyllenhall plays the real Robert Graysmith, according to Graysmith's book. He was a normally shy and timid political cartoonist who became obsessed with finding the identify of the serial killer, Zodiac.
Mark Ruffalo and Anthony Edwards play inspectors David Toschi and William Armstrong of the San Francisco police. And, Elias Koteas plays Sgt. Jack Mulanax of the Vallejo police.
Graysmith wrote the novel about the Zodiac murders of northern California and the search for the killer who called himself Zodiac. The story takes place from 1969 into the 1990s. And the mystery has not yet been officially solved.
I haven't read Graysmith's book of the same title. But I can recall the headlines and gist of the Zodiac killings from the news of that time. The movie does a good job of showing the intensity of the main people involved in trying to crack the case. It also shows an initial lack of cooperation among local police departments. No doubt, the Zodiac killings were a wake-up for law enforcement entities to eagerly cooperate to solve crimes in the future.
In spite of the earnest efforts of the principal investigators, the movie (if not the book also) shows some weaknesses and mistakes that probably kept the law from solving the crimes. One weakness was in the heavy reliance at the time on handwriting analysis. The conclusion by the handwriting expert, Melvin Belli (played by Brian Cox) was taken flatly as proof that various suspects were not Zodiac. That included the most likely suspect, Arthur Leigh Allen. Although still used today, handwriting is highly disputed. If some people can fool a lie detector test, some surely could alter or modify their handwriting sufficiently to fool the analysts.
The movie shows two glaring mistakes or oversights. When Toschi and Armstrong interviewed Arthur Leigh Allen at his work, they were highly suspicious of him. Why didn't they get an immediate search warrant for his residence? We learned later that in less than 48 hours, Allen moved a lot of stuff out of his residence. So, when the police finally did search the place, they found nothing incriminating. But the biggest error was in not pursuing Michael Mageau after he moved away. He survived the July 4, 1969 shooting that began the Zodiac's spree. And, he was the one and only person who saw the killer's face and could identify him.
Indeed, the scene at the very end shows Mageau picking Arthur Allen's photo out of several shown him. Officer George Bawart had replaced the retired Jack Mulanax in the Vallejo police department. He met with Mageau in 1991, and Mageau was quick to identify Arthur Allen as the person who shot him 22 years earlier. Had the police tracked down Mageau in 1969 or 1970, they would have had Zodiac convicted on the basis of an eyewitness survivor, supported by much circumstantial evidence.
Instead, the movie shows what happened 22 years after the start of Zodiac's killing spree. Before the police could charge Allen with the murders, after Mageau's 1991 ID of him, Allen died of a heart attack. So, that one big mistake by the police in 1969-70, led to years and years of searching, checking, and working by several people - all without a solution. The movie never explains why the police did not try to go after Mageau to have him look at photos of suspects.