Katherine Hoover, five months pregnant with a boy she already knew as Rehlin, was eating McDonald’s at the DeHayes family kitchen table in Brooksville, Florida, as 35-year-old William DeHayes—an old friend of her new husband, Carson—showed off his collection of guns. First, he unstrapped the 9mm from his leg, then got out an old shotgun from the bedroom.

Moving on, DeHayes used a Western-style draw (“kinda like a cowboy would,” he later explained to police) to unholster an antique revolver that had belonged to his grandfather. DeHayes had been practicing gun slinging tricks he learned on YouTube—a hobby he picked up to give himself purpose after getting on permanent disability for back pain. “Something I can be proud of,” DeHayes said to investigators.

Carson gave the revolver a look and handed it back. DeHayes spun the gun again, put his finger on the trigger, and eased the hammer to put it back in the holster.

That’s when the gun fired. The single bullet—which DeHayes swears he never loaded—entered Katherine’s temple. The 25-year-old was rushed to the hospital, where she died soon after. Doctors delivered Rehlin via Caesarean section, but he died 30 minutes after his mother.

Katherine’s family was heartbroken by the loss, but now say insult has been added to injury by the state prosecutor’s decision not to press charges against the man who killed her and her baby.

“They prosecute people for drowning dogs. Do you know how this makes me feel?” Katherine’s mother, Donna Bryan, said in a phone interview. Bryan has been petitioning the state attorney, Brad King, as well as her senators, state Attorney General Pam Bondi, and Governor Rick Scott, in the hope that someone will try her daughter’s killer for involuntary manslaughter.

So far, she’s been unsuccessful.

“There is no evidence to suggest the [sic] DeHayes had a careless or reckless indifference to the safety of the victims when the firearm discharged,” assistant state attorney Brad Magrino wrote in his recommendation not to prosecute.

Bryan’s push to get state attorney Brad King to investigate further or bring the case before a grand jury was met with a another clear dismissal. According to King, for a crime to have occurred, DeHayes would have had to pull the trigger intentionally. In a letter denying her case, King wrote that an accidental discharge of a firearm that kills someone—even if it is the result of gross negligence—cannot be prosecuted.

“Just as it is my duty to prosecute those who violate the law, it is equally my duty to refrain from prosecuting those whose conduct, no matter how outrageous, does not constitute a crime,” King wrote.

The explanation has done little to console Katherine’s husband, Carson, who says he still can’t sleep without playing the night over in his mind and thinks something more should be done. “I know William wouldn’t have done something like this on purpose, but I’ve lost two very special people in my life that I can never get back because of his negligence,” Carson said in a phone interview. “I want to see justice done.” (Carson is considering a civil action.)

Both Carson and his mother-in-law feel there are extenuating circumstances that put DeHayes at fault.

In an interview with the Hernando County sheriff obtained by The Daily Beast, DeHayes goes over the events of that evening. Breaking into sobs throughout the recording, DeHayes tells an investigator, “I haven’t slept in three days trying to figure out how the hell [the gun] went off. I don’t know. I mean them damn guns. The shotgun goes off when it wants to. I almost blew my damn head off twice.” The pistol that killed Katherine was found to be in working order by the Florida Department of Law Enforcement.

Added to what Katherine’s family sees as a history of unreliability and improper care of his guns, DeHayes also told the sheriff he had taken a number of prescription drugs an hour before the shooting—methadone and Loratab, opiods for pain and Soma, a muscle relaxer, all to treat what he said are diagnosed “severe back problems.” DeHayes said he only took the medication in the prescribed amounts, however, and officers did not note any behavior at the scene that would indicate he was under the influence.

DeHayes no longer works due to his disability and lives at home with his new wife and her three children. It’s unclear if he still practices gun slinging, but DeHayes often posted pro-gun messages to his now-deleted Facebook page from The National Association for Gun Rights. In a tragically ironic message, two months before Hoover’s death, DeHayes posted a photo of a gun with the text, “Left My Gun Alone Today. It Didn’t Kill Anyone,” and the additional caption, “Yep, proving once again that the lethality of an object is entirely dependent on the intent of the operator.” As far as Bryan knows, DeHayes’s guns were returned after the investigation and presumably remain in his possession.

Calls to DeHayes and emails asking for comment were not returned.

It’s hard to say just how often shootings like the one in Brooksville occur. Shooting deaths overall have steadily declined over the years, a trend that public health officials attribute to medical care as much or more than a commitment to gun safety or reduction in crime.

But when it comes to unintentional gun deaths—of which there were 505 in the U.S. in 2013, 22 in Florida alone, according to the CDC (PDF)—the data is too messy to be parsed. In some cases, deaths caused by someone who had no ill intent are labeled homicides. The Florida medical examiner in fact classified the deaths of Katherine Hoover and her unborn son, Rehlin, to be homicides, so they won’t appear as unintentional deaths in the CDC’s Vital Statistics data.

Though accidental gun deaths are far from commonplace, injury prevention researchers say these—mostly of children and very young adults at the hands of friends or family members—are far too common, and almost always preventable. “Guns are deadly. You handle them over and over and nothing happens,” said Dr. David Hemenway, director of the Harvard Injury Control Research Center. “People get used to taking short cuts and not being as safe and that’s when problems happen. And the more you play with your guns, the more likelihood that there is going to be an accident.”

The state attorney’s decision not to prosecute DeHayes in Kathleen’s death is far from the first time he’s been criticized for letting someone off easy. Brad King made national news in 2013 when PBS’s Frontline and The New York Times uncovered a bungled investigation into the suspicious shooting of Michelle O’Connell, a sheriff deputy’s girlfriend, whose death was ruled a suicide. In that case, despite forensic data and a number of experts and witnesses pointing to the the deputy’s alleged guilt, King told reporters, “There was not sufficient evidence a crime had been committed.” Due in part to pressure from the media coverage, Governor Rick Scott issued an executive order reopening the investigation in October of last year.

Donna Bryan is hoping similar national attention might spur action on her daughter and grandson’s behalf.

“This has to be prosecuted,” Bryan said. “No matter what, I’m not going to stop.”