A school shooter's mother has been convicted. Victims' parents say it sends a message.

Tony Montalito still feels sadness surrounding the mass school shooting that took his daughter's life in Parkland, Florida, in 2018. But on Tuesday, he also felt some sense of justice.

The jury decision in Michigan that found Jennifer Crumbley, the mother of a school shooter, responsible at least in part for the 2021 killings at Oxford High School sends an important signal, Montalito told USA TODAY. It offers parents of shooting victims some hope that people will take steps to keep guns away from their children.

"Holding people accountable for their roles in not actively trying to get troubled individuals help before they commit acts of violence will send a strong message," Montalito said. "It shows how we all need to come together as parents, students and teachers. It's the start of the process. There's not one solution to this problem."

The jury's decision is the first time the parent of a school shooter has been found guilty of involuntary manslaughter for their part in a mass killing. The Oxford shooting left four dead and seven others injured.

The case could alter the future of gun violence in America and how parents are held liable for what their kids do with firearms kept in their homes, legal experts, gun control advocacy groups and families affected by gun violence told USA TODAY.

In all, 17 were killed and 17 were injured at Marjory Stoneman Douglas High School in Parkland on Feb. 14, 2018. On Tuesday, Parkland parents were "happy to see some accountability from a jury, because sadly in Parkland, we couldn't find a jury who found the shooter or school resource officer fully accountable for the murder," Montalito said. The killer in the Parkland case, Nikolas Cruz, 19 at the time of the murders, was sentenced to life in prison without parole, but the jury deadlocked on imposing the death penalty.

What happened in Michigan?

On Nov. 30, 2021, Ethan Crumbley shot and killed four of his classmates and injured seven others, including a teacher, with a gun that his parents had bought for him.

The Michigan jury in Jennifer Crumbley's trial found her responsible for the murders of the four students. During the trial, Crumbley portrayed herself as a doting mother who wasn't aware of her son's mental health struggles and said the responsibility to secure the gun belonged to her husband, James. He is scheduled to go on trial March 5.

But the jury sided with prosecutors who said Crumbley and her husband knew their son was struggling with his mental health − including on the morning of the shooting − but didn't get him help. Prosecutors also said the parents tried to flee from law enforcement.

“Today’s verdict underscores the important responsibility of parents and gun owners in preventing children from having unsupervised access to deadly weapons," said Nick Suplina, senior vice president for law and policy at Everytown for Gun Safety. "Plain and simple, the deadly shooting at Oxford High School in 2021 should have − and could have − been prevented had the Crumbleys not acquired a gun for their 15-year-old son."

Kris Brown, president of gun control advocacy group Brady United, said the ruling has brought some justice to the victims’ families.

“Today’s decision sends a powerful message to parents and other parties that they can be responsible for their actions that foreseeably contribute to gun violence even if they don’t pull the trigger,” Brown said.

Craig Shilling’s son, Justin, 17, was killed by Crumbley’s son in a high school bathroom. Shilling appeared stoic when the verdict was announced. He bowed his head with clasped hands as he listened to the word "guilty" echoing four times in the otherwise silent courtroom.

"I’m happy with the verdict even though it’s still a sad situation to be in," Shilling told reporters after the verdict. “I feel that this verdict is going to echo throughout every household in the country."

Jennifer Crumbley verdict: After historic trial, jury finds mother of school shooter guilty

What does the decision mean for America and the future of gun violence?

According to a 2019 U.S. Secret Service report, 76% of school attackers get firearms from the home of a parent or other close relative. In half of the firearms cases, the weapon was either readily accessible or not securely stored, the report says.

Some experts say Tuesday’s verdict could have a ripple effect on future school gun violence cases.

“On the one hand, we might say that uniquely bad facts make for a unique case,” said University of Michigan law professor Ekow Yankah. “On the other hand, the life of the law is precedent, and now that this precedent is out there, prosecutors are going to know that they have another tool in their kit.”

Everytown for Gun Safety's Supline called the jury's decision "an important step forward in ensuring accountability and, hopefully, preventing future tragedies."

David Riedman, founder of the K-12 School Shooting Database, said he "hope(s) that seeing a parent headed to prison will make other parents think twice before they leave a gun accessible in their home."

"Every school shooting committed by a teen who is too young to purchase a firearm would be prevented if the legal owner kept the weapon secured," Riedman said. "This verdict was critical to place responsibility on the adult who purchased the weapon. ... School shootings committed by students can't happen when kids can't access a gun."

On the other hand, Dan Feldman, a professor at the John Jay College of Criminal Justice, said he agrees with the Michigan jury's decision, but he's not confident it sets a legal precedent because the outcome of the case doesn't seem out of line with other involuntary manslaughter cases.

Jennifer Crumbley's lawyer Shannon Smith said the case could set a dangerous precedent for parents who are trying to do their best for their children.

"This is not justice. This is not how justice works," Smith said. This does nothing for people who have lost everything … and it does nothing to (undo) the tragedy that unfolded on Nov. 30."

Parents, states apart, mourn the loss of students killed by school shooters

Valentine's day marks the six-year anniversary of the deaths of Montalito's daughter Gina and of her schoolmates at Parkland.

"We wish the jury held accountable those responsible to fullest extent of the law," Montalito said. "Just like the families in Oxford who miss their kids, every day I miss my daughter Gina. And the families in Parkland miss their kids."

Contributing: Tresa Baldas, Gina Kaufman and Keith Matheny; the USA TODAY Network

Contact Kayla Jimenez at kjimenez@usatoday.com. Follow her on X at @kaylajjimenez.

This article originally appeared on USA TODAY: Jennifer Crumbley conviction: Shooting victims' parents speak