SANTA FE, Texas – Rhonda Hart knows her daughter, Kimberly Vaughan, died quickly when a spray of shotgun pellets and pistol bullets tore through her stomach and inner organs.

But there's still a lot she doesn't know about last year’s shooting at Santa Fe High School: How did the alleged shooter enter the school? What time? Were there any red flags about the suspect? Why was he allowed to wear a trench coat to school?

"It's been really frustrating," Hart said. "They've kept us in the dark."

A year after the attack May 18, 2018, that claimed 10 lives and injured 13 at Santa Fe High, Hart and other relatives of victims and survivors say they still don’t have many details. The families are calling for an independent, third-party review of the shooting to learn what went wrong and prevent future shootings – in Santa Fe and elsewhere.

Unlike last year’s shooting at Marjory Stoneman Douglas High School in Parkland, Florida, where authorities quickly released a timeline of the attack, formed a commission and produced a detailed analysis of the incident, some Santa Fe parents say Texas officials, citing the ongoing investigation and upcoming trial, are withholding important details.

Shortly after the shooting, Gov. Greg Abbott convened a series of roundtable discussions with experts and parents and later released a 40-point action plan. State lawmakers passed many of those recommendations into law this session, including money for student risk assessment and mental health initiatives.

But families say more is needed, such as a robust third-party investigation into the shooting.

“Nobody is being held accountable,” said John Rosenboom, whose son Colby was shot in the hip and survived. “It’s a shame we know more about the Parkland shooting than the shooting that happened right here in our own town.”

Authorities say Dimitrios Pagourtzis, 18, a junior at the high school, opened fire in two crowded art classrooms using his family’s sawed-off Remington shotgun and a .38 handgun. Students hid in supply closets and scrambled under desks as the suspect repeatedly shot at and taunted his classmates before surrendering to police, according to court documents and witnesses. He has been charged with capital murder and aggravated assault on a peace officer.

Pagourtzis may also face federal charges, though the nature of those charges are not known because federal law prohibits public hearings for juveniles. Pagourtzis was 17 at the time of the shooting.

Glenda Ann Perkins, 64, a substitute teacher at Santa Fe High, was shot and killed leading a group of students out an exit. Her husband, Steve Perkins, said he has received frustratingly little detail about the shooting, despite repeated trips to the Galveston County District Attorney’s Office and meetings with police officials and federal prosecutors.

He said he’d like to know the exact timeline of events, how many times his wife was shot and how long his wife may have lived after being shot – details authorities have refused to share.

“You lay in bed and you think about, ‘What were her last moments? What really happened to her?’” he said. “The answers are out there. All they got to do is let me see them.”

After the shooting, Steve Perkins walked around in a fog of crippling mental pain. Slowly, he has processed the loss but thinks about and misses his wife each day, he said.

Getting more details about her final moments would bring much-needed closure to the event, he said. He's not giving up, he said.

"We’re going to get to the bottom of this," Steve Perkins said. "Sooner or later, they're going to have to answer."

Like others, Perkins voiced frustration that authorities in Florida have been much more open with details about the Parkland shooting than Texan officials have. In that incident, on Feb. 14, 2018, a former student at Marjory Stoneman Douglas High opened fire inside the school, killing 17 students and staff members and injuring 17. The suspected shooter, Nikolas Cruz, awaits trial on 34 counts of premeditated murder and attempted murder.

Three weeks after the attack, the Broward County Sheriff’s Office released a detailed timeline of the event, and several officials, including Broward County Sheriff Scott Israel, were fired for mishandling the shooting and its aftermath. Florida lawmakers also created a commission that included parents of victims and led to a 439-page report dissecting the shooting.

The report used surveillance video, police body-worn cameras, cellphone videos, police reports and witness testimony to stitch together a minute-by-minute account of the shooting, highlighting where things went wrong and suggesting improvements. Last month, some of those recommendations, including enhancing mental health services for students and improving threat assessments at schools, were signed into law.

Key to the changes was having an independent commission with the power to subpoena people and records, said Florida Sen. Bill Galvano, who wrote the bill that led to the commission.

“It brought the discussion to a new transparent level,” he said. “We had to hear and understand what went wrong and what didn’t.”

The Santa Fe Independent School District has implemented new changes, such as metal detectors at all its schools and changes in door locks and alarm systems. But a third-party assessment of the shooting does not appear to be in the works.

J.R. “Rusty” Norman, president of the Santa Fe School Board, said the board is waiting to see what the criminal investigation unearths before taking further steps. The Texas School Safety Center, a research center at Texas State University in San Marcos, is conducting a district-wide evaluation of policies and procedures but not looking specifically at the 2018 shooting, Norman said.

And even results of that study may not be made public, he said. “You’re talking safety and security measures,” Norman said. “We’re not going to expose flaws to someone who can be a potential perpetrator down the road.”

Jack Roady, Galveston County’s district attorney, said he sympathizes with parents frustrated by the lack of information. But an exception to the Texas Public Information Act, known as the “law enforcement” exception, allows prosecutors and other officials to withhold information if its release could jeopardize an investigation or upcoming trial.

Releasing details of the shooting could taint the testimony of witnesses at trial and compromise a fair trial for the defendant, he said. Roady said he plans to lobby Texas lawmakers in the coming months to tweak the law so he can share info with families of victims and survivors without having to release it to the public.

“It’s heartbreaking that we have to tell them, ‘Not yet,’” he said. “I wish we could share that information. We’re just not able to at this point.”

A key question some families have is whether the suspect had any disciplinary marks on his record that may have alerted school officials to his state of mind. The Florida report on the Parkland shooting revealed that authorities missed multiple red flags with that shooter, including incidents with the Broward County Sheriff's Office and tips to the FBI that went unheeded.

Students have said Pagourtzis wore a long jacket or trench coat to school in the months leading up to the shooting, which is against school code policy and should have alerted school officials.

Another puzzling event to parents was a lockdown in late February, three months before the shooting, when several bangs were heard outside the school and students were made to shelter in their classrooms. Police didn't find any sign of foul play, according to a police report of the incident.

But parents question whether there was any connection to the May 18 shooting.

Colby Rosenboom recovered quicker than other survivors, but mental scars lingered. In the first few months after the shooting, he'd get anxious in crowded places, like the mall, said his father, John Rosenboom.

He and wife, Dawn Rosenboom, have lobbied school officials for more information, including details on the shooter's past. That information would bolster their confidence that the school is doing everything possible to prevent another shooting, Dawn Rosenboom said.

The lack of details has only added to their anxiety, she said.

"It's disheartening," Dawn Rosenboom said. "We’re probably the most uninformed group of parents on the planet as far as what happened."

Hart said she sent several Freedom of Information Act requests to try to get more details, only to get reply letters from Texas Attorney General Ken Paxton's office denying the requests.

Rebuffed by authorities, Hart turned to Google and discussions with her dad, a former hunter who knew about gunshot wounds, to try to learn more. After a brief, informal phone chat with the Galveston County Medical Examiner, she scoured the internet and deduced that the close-range shotgun blast probably tore through Kimberly's liver, spleen, heart and lungs, likely killing her quickly. She still hasn't seen her daughter's autopsy report.

Hart said she's also interested in what school officials knew about the suspect before the shooting. As a former bus driver for the Santa Fe ISD, she would routinely call in reports of troubled students, she said.

"Somebody at some point should have seen this kid wasn’t doing well," Hart said. "Somebody missed a step with this kid and I want to know why."

Not all family members are frustrated by the lack of information. Sonia Lopez, mother of shooting victim Sarah Salazar, said she understands prosecutors need to preserve the integrity of the trial. Sarah survived but has undergone months of painful physical therapy to repair injuries to her shoulder and neck.

Lopez said she also wants to know more details of the incident but is willing to wait until they come out at trial.

“It is what it is,” she said. “We trust God that he’s brought us this far and he’ll get us through it.”

But independent investigators should be talking to witnesses now, while memories are still fresh – not wait any longer, said Flo Rice, a substitute teacher at Santa Fe High. Rice was hit with several shotgun blasts from the shooter as she escorted students away from the incident. Glenda Ann Perkins died a few feet away from her.

Details of the shooting and an analysis of what may have gone wrong could help other schools around the country better prepare for a mass shooter, she said. There have been at least three other school mass shootings since the Santa Fe incident.

In December, Rice and other survivors met with Abbott at the governor’s mansion in Austin and urged him to create an independent, third-party commission to fully investigate the shooting. Abbott said he would make it a top priority, she said.

So far, there's no sign of an independent review, Rice said.

“We’re not protecting our children,” she said. “If you can’t learn from the past, it’s going to continue happening.”

Follow Jervis on Twitter: @MrRJervis.