Inaccurate
Mike Mageau never got a good look at the shooter. Arthur Leigh Allen was later exonerated by further evidence, although remains a person of interest. The case remains unsolved.
shareTo be technically accurate, one can only be exonerated if they have first been convicted of a crime. Allen was never convicted of anything.
That said, I'm still not sure I understand your statement. It sounds like you are saying he was cleared of suspicion by authorities but still remains a person of interest. Why would he still be a person of interest if they had no reason to suspect that he may have been the perpetrator.
“While spokesmen for the Vallejo police department have stated at various times over the years that Allen remains a person of interest in the investigation, all of the law enforcement agencies mentioned in the end titles of the film still investigate other suspects and other leads. Investigators from the Napa County Sheriff’s department, including Ken Narlow, do not believe that Allen was the Zodiac. The end titles make no mention of Allen’s suspect status with the one law enforcement agency at the center of the film’s plot – the San Francisco police department. At the turn of the century, the SFPD had little interest in Allen after announcing the results of DNA comparisons that appeared to exonerate the suspect, and the news that a “writer’s” palm print, found on the Zodiac’s infamous “Exorcist” letter, did not match the palms of Arthur Leigh Allen.”
“All of the law enforcement agencies involved in the Zodiac investigation consider the case unsolved.”
https://zodiackillerfacts.com/myths-legends/zodiac-the-movie-fact-vs-fincher/8-fact-vs-fincher-scene-by-scene-71-thru-the-end/