While the historic trials of the parents of Michigan school shooter Ethan Crumbley resulted in guilty verdicts, the parents of the four students killed at Oxford High School in 2021 said Monday their quest for accountability is far from over.

They are turning their attention back to the school district and school administrators, some of whom were called as witnesses in the trials, to demand lasting efforts from state leaders, including changes to governmental immunity laws that protect schools from being sued and requiring independent reviews after any mass shooting.

They also want a continued investigation into the response at Oxford, with subpoena power to force people to cooperate, saying a third-party report released last year was “scathing” but also had shortcomings, in part, because school employees weren’t compelled to participate.

“We’re not fighting for us anymore,” said Steve St. Juliana, whose 14-year-old daughter, Hana, was among those killed in the worst school shooting in Michigan’s history.

“Our children are dead. They’re not coming back,” he added. “We’re fighting for everybody else and to try to wake people up to realize that what happened here in Oxford can and will happen again.”

The parents called for wider changes after the Oakland County Prosecutor’s Office said, following James Crumbley’s conviction of involuntary manslaughter last week in the students’ deaths, that it wouldn’t bring additional criminal charges against school officials.

“If I were going to charge anybody criminally in the school, I would have done so, and I would have stated it,” County Prosecutor Karen McDonald told NBC News on Friday.

McDonald’s office worked closely with victims’ families in her pursuit to secure charges in the unusual cases against James Crumbley and his wife, Jennifer, who was convicted last month on the same involuntary manslaughter charges. During the trials, prosecutors evoked the names of the victims — Hana St. Juliana; Justin Shilling, 17; Madisyn Baldwin, 17; and Tate Myre, 16 — in their opening statements and closing arguments.

St. Juliana said he isn’t giving a lot of credence to a local news report over the weekend that multiple school employees were given assurances that McDonald wouldn’t prosecute them, prompting her office to say in a statement that “any suggestion that any school employee was offered immunity or protection from prosecution” is false.

“While we would love for certain officials there to be criminally charged,” St. Juliana said, “the fact of the matter is it’s a high bar to meet those criminal charges.”

The trials against the Crumbleys were already a landmark — the first time prosecutors in the U.S. had held parents responsible for their child’s mass school shooting. Ethan Crumbley pleaded guilty as an adult to murder, terrorism and other charges and was sentenced to life in prison.

To help prove its case that his parents’ actions ultimately helped lead to the massacre, the prosecution called Oxford High School staff members to discuss the day of the shooting in November 2021. Administrators had summoned the Crumbleys to the school that morning in response to a picture that Ethan, then 15, had drawn of a gun, a person who had been shot and the message “The thoughts won’t stop. Help me.”

Staff members testified that the Crumbleys never warned them that Ethan had access to a firearm from home and that his parents declined to take him home after the meeting. The teenager would go on to commit the shooting hours later with a 9 mm Sig Sauger handgun bought for him days earlier by his father.

James Crumbley told investigators he hid the weapon in an armoire and placed the ammunition underneath jeans in another drawer. Ethan didn’t testify in the trials, and while his journals and text messages were used to show his deteriorating mental state, prosecutors suggested his parents ignored and failed to get him treatment.

But the defense lawyers for James and Jennifer Crumbley in their respective trials also deflected the blame onto school administrators, who were similarly made aware that Ethan was struggling.

Shawn Hopkins, a counselor at Oxford High School, testified that Ethan had wanted to remain in school after his parents went to the meeting and that instead of insisting they take him home, Hopkins agreed he should stay.

“I made the decision I made based on the information I had,” Hopkins said. “I had 90 minutes of information.”

Nicholas Ejak, Oxford High School’s dean of students at the time of the shooting, testified that he had picked up Ethan’s backpack from his classroom on the morning of the meeting and joked that it was heavy. But no one thought to check the bag, which is where the shooter hid the handgun and ammunition.

During closing arguments at James Crumbley’s trial, McDonald was clear to the jury that the school had made its share of missteps, as well.

“You may not like what the two people who were employed by the school and had contact with the Crumbleys that day did,” she said. “But my job isn’t to present to you the evidence that just looks good for my case. My job is to present evidence to you, all of it, because this is about the truth.”

Since the shooting in suburban Detroit, families of students have sued the Oxford school district, but there remains legal wrangling over whether it can’t be sued because of governmental immunity. A county circuit judge found in March that “because it is undisputed that the school district was a governmental agency” at the time of the shooting, it “is immune from tort liability.”

Ven Johnson, a lawyer for some of the families, said in a previous statement that governmental immunity puts an increased burden of proof on victims in proceedings against governmental employees and that “the law should be changed immediately.”

The Oxford school district didn’t immediately respond to a request for comment Monday.

Lawyers for the Crumbleys have expressed respect for the victims’ families. James Crumbley’s lawyer, Mariell Lehman, told NBC News on Monday that he personally “feels terrible about what happened to those families.”

“This was an incredibly emotional trial,” Lehman said.

St. Juliana said Monday that besides a more thorough and transparent investigation into the shooting, board members must also step down to help the community heal. He’s worried, he added, that some people just want to move on, especially now that the trials are over.

“The school’s official position is they did nothing wrong,” St. Juliana said. “Everything has been done wrong in Oxford. It’s too late to do it right in Oxford. But Oxford is the opportunity to learn, right? So that’s how you learn from your mistakes.”

In the aftermath of the trials, McDonald said she is forming her own commission to share recommendations and help prevent mass shootings “way upstream, to teach and prevent people and kids from becoming in a place of crisis,” treating gun violence like a public health crisis.

“It’s not just teach kids to run, hide, fight,” McDonald said. “There’s so much more we could be doing.”