The call for action is coming from some of the families of the Santa Fe High School shooting, where eight students and two substitute teachers were killed on May 18, 2018.
Since that time, the autopsy reports of each victim have remained non-public.
"For three years, we've been asking, and we've been denied every single time," said Rosie Stone.
Her son Chris Stone was 17 years old, a junior at Santa Fe High School at the time, who never came home.
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Galveston County District Attorney Jack Roady told ABC13 the autopsy information for each victim is part of trial evidence and is protected by law.
But it took filmmaker Charlie Minn just one phone call to Barnhart in May 2021 to get the very information these families have been requesting for years.
"She gave me a lot of information, specifically about how many times each victim was shot and what part of their body was hit," said Minn.
The documentary filmmaker said he called Barnhart one time after corresponding with her by email.
During the single phone conversation, she shared autopsy information and allowed one of her technicians to be interviewed for his documentary.
The Galveston County District Attorney's Office is defending the medical examiner saying in part, "It was unfortunate this filmmaker used deception to get this information, however, we stand by the work of the Galveston County Medical Examiner and have full faith and confidence in Dr. Barnhart."
Jack Roady tells ABC13 Barnhart reported that the filmmaker misled her into revealing the information.
Minn denies misleading or lying in order to get the autopsy details saying, "To me, that sounds like someone who is just trying to protect themselves, and they'll say anything. That's pathetic if that's indeed what she said. I reached out to her needing information for a documentary and she was more than open to giving it to me."
ABC13 called to speak with Barnhart twice on Friday, but an employee told us she had no comment.
Since this leak of information, the district attorney is now allowing the families to learn the same information that was given to Minn.
Stone said she's happy to finally have access to information about her son's death, but she still questions why it was given to a filmmaker first.
"How does it even sound right that literally a stranger from New York called and said, 'Hey, I'm doing a documentary, would you like to talk to me?' and she said, 'Oh yea,' and when I call, literally crying, she can tell you I've called crying, just to be told 'Sorry. I'm sorry. I can't give you any information,' and I have to hang up empty-handed," said Stone.
The district attorney told ABC13 officials are not investigating the leak of information and said he does not believe it will jeopardize their prosecution.
Minn's film, "The Kids of Santa Fe: The Largest Unknown Mass Shooting," will include the autopsy information of each victim.
"My films are victim driven," said Minn. "They're meant to give the victim's a voice, to recognize and honor them. The killer's name is not mentioned once in the entire film. This is completely victim, survivor-driven, and that's how all my movies are."
The documentary will premiere on Sept. 10 at the Premiere Cinemas in Pearland. There is a sneak preview showing for a limited audience on Tuesday, Aug. 31.
For updates on this report, follow ABC13 reporter Shelley Childers on Facebook, Twitter and Instagram.