It comes from his mother’s cell phone outside the office doors of lawmakers on Capitol Hill. The disembodied voice of the 17-year-old, who was a student at Marjory Stoneman Douglas High School, has a message to deliver.

“Six years ago, I was a senior at Parkland. Many students and teachers were murdered on Valentine’s Day that year by a person using an AR-15 assault rifle,” the voice says. “It’s been six years, and you’ve done nothing. Not a thing to stop all the shootings that have continued to happen since.”

“The thing is, I died that day in Parkland,” the voice continues. “My body was destroyed by a weapon of war. I’m back today because my parents used AI to recreate my voice to call you.”

The audio is one of six AI-generated voice messages from young people killed by gun violence, part of a new campaign launched last week by two groups, March For Our Lives and Change the Ref, to urge lawmakers to act on gun control.

“My wife and I have been trying to use our voices for the last six years. Nonstop. We have tried almost every single way to approach gun violence in a way that people will pay attention. We haven’t been very successful,” says Manuel Oliver, who founded the Change the Ref advocacy group in memory of his son after the 2018 shooting in Florida.

“So we decided, you know what? Let’s bring the voices of our loved ones. Let’s bring the voice of Joaquin.”

The new campaign’s website, called The Shotline, invites people to listen to the voice messages, enter a zip code and send calls to members of Congress.

The campaign launched the same day a mass shooting at a Super Bowl victory parade in Kansas City killed one person and wounded more than 20 others, including children. There have been 50 mass shootings in the United States so far this year, according to the Gun Violence Archive.

Uzi Garcia, 10, who died in May 2022, is one of the six children featured in the campaign.

“I love video games, telling jokes and making my friends laugh and jumping on the trampoline with my family,” Uzi’s AI-generated voice says in his message. “I’m a fourth grader at Robb Elementary School in Uvalde, Texas. Or at least I was when a man with an AR-15 came into my school and killed 18 of my classmates, two teachers, and me. That was almost two years ago. Nothing has changed. Even more shootings have happened.”

Uzi’s father, Brett Cross, told CNN he spent hours going through old playground videos on his phone to get the right audio of Uzi’s voice. He says he worked with the campaign’s technology team to make sure the pitch was just right and he listened to Uzi’s AI voice over and over before he signed off on its use.

“It was bittersweet because we get to hear his voice again,” he says. “But he should be here to speak for himself, and he’s not. So we have to get more and more creative to get these politicians to listen to us.”

Cross says he understands that employing the voices of dead children to plead for gun control bothers some people. He says critics on social media have described the campaign as unethical and “ghoulish” and have accused him of using his son as a ”pawn” to push a gun control agenda.

But he told CNN he’s unfazed by the criticism.

“If you think it’s uncomfortable hearing my son’s voice after he’s passed, imagine what it’s like to be us — to live with this every day,” he says.

Since the campaign launched, more than 54,000 voice calls have been sent so far to lawmakers, according to a tally on The Shotline site.

The campaign features four other victims of gun violence:  Ethan Song, 15, of Connecticut, who died in an accidental shooting in 2018; Akilah Dasilva, 23, who was killed in a 2018 mass shooting in Tennessee; Mike Baughan, 30, of Maryland, who died by suicide in 2014; and Jaycee Webster, 20, who was shot and killed at his Maryland home in 2017.

More than two dozen other parents have contributed audio of their children’s voices to the campaign for potential use in future calls, Manuel Oliver says.

The campaign comes as rapid advances in AI technology have made it easier to recreate people’s likenesses and voices, allowing scammers and other bad actors to send fake and manipulative messages.

The Federal Communications Commission allows political prerecorded voice calls made to landlines, even without prior consent. But earlier this month, it  announced that robocall scams using AI-generated voices are a violation of telecommunications law. The announcement came after an AI-generated robocall that sounded like President Biden circulated to New Hampshire voters ahead of the state’s January primary election, telling them to stay home.

The Shotline’s messages are sent to lawmakers’ landlines and make it clear that the voices are AI-generated, Oliver says.

One expert told CNN the parents are likely not breaking FCC law because they’re transparent about their use of AI and their aim is not to defraud.

“If you evaluate this call from that perspective, it’s clear up front it’s AI generated, so if they have permission from the families of the voice they’re using, and they’re not violating the TCPA (Telephone Consumer Protection Act) in some other way, it would be fine,” says Alex Quilici, CEO of YouMail, a robocall-blocking service. “Think about the old ads that said ‘celebrity voice impersonated’ — we were all good with those.”

But for some, using AI-generated voices of dead people in a gun control campaign may raise ethical concerns.

“It does seem to kind of straddle the line between a good use of AI and something that’s questionable,” says Robert Wahl, an associate professor of computer science at Concordia University Wisconsin and an expert on the ethics of AI technology.

Creating AI voices is a nuanced process that involves numerous adjustments to make sure the inflection, timing and pitch are as close as possible to the original voice and don’t sound robotic, he says.

“It’s interesting because Hollywood has been doing this kind of thing for a while with recreating dead actors,” he told CNN. “And of course the technology is evolving almost on a daily basis. But I think it’s nice to be able to recreate a voice, as long as it’s OK with the immediate family.”

Manuel Oliver says he understands some people’s discomfort with the campaign’s AI-generated voices. He says some parents who’ve lost children to gun violence were reluctant to take part in the project.

But his goal is to jolt members of Congress and others into action on gun laws. And he says if it bothers some people — well, that’s the point.

“If bringing the voice of a victim alive using technology in a transparent way … If that makes you feel uncomfortable, but you’re OK with kids getting shot at parades and schools, then something’s wrong with you,” he says.

“No one should tell me what the hell uncomfortable is … because I can tell you what feeling uncomfortable is. It’s not being able to see my son ever again.”