Gavin Guffey sent a message to his younger brother and friends in the predawn hours of July 27 last year. It was short and cryptic: The heart-shaped symbol of love -- <3 -- on a Black background.

Minutes later, in a hallway bathroom a few steps from his room, the 17-year-old fatally shot himself. His father, Brandon Guffey, says he was at their home in Rock Hill, South Carolina, when he heard a loud thud -- almost like someone had slammed a bowling ball to the floor.

He rushed to the bathroom and found his oldest son bleeding on the floor between the tub and the toilet.

For weeks, the grieving family searched for signs of anything they'd missed. Then they found out that scammers masquerading as a young woman had sent Gavin nude photos -- and asked him for similar images of himself. Once Gavin shared photos with them, they blackmailed him with a threat to publicize them if he didn't pay.

Gavin had unwittingly become a victim of sexual extortion, or "sextortion," a crime the FBI warns is increasingly targeting underage boys. Sextortion cases have gone up in the past year, federal officials said in a recent safety alert issued in partnership with the National Center for Missing and Exploited Children. The cases are contributing to an alarming number of suicides nationwide, the alert said.

At the the time of his son's death, Guffey, 43, was running for state House representative. Six months later, after a winning campaign, he assumed office. His first order of business was to introduce a state bill to criminalize the type of scam that led to his son's death.

His fellow House lawmakers unanimously passed the bill last month. State senators passed the legislation Thursday -- naming it "Gavin's Law" -- as a tearful Guffey watched from senate chambers.

Under the law, scammers who extort a minor or an at-risk adult will face up to 5 years in prison for a first offense.

Lawmakers are expected to send the bill soon to Gov. Henry McMaster to be signed into law.

For weeks, the family tried to unravel the mystery surrounding his death

Guffey and his wife Melissa have spent months trying to untangle the mystery surrounding their son's death.

In the weeks after the funeral, the scammers barraged Guffey and his younger son, Coen, 16, with Instagram messages demanding money in exchange for the nude photos. One message, sent to Guffey's Instagram inbox on August 20, the day Gavin would have turned 18, outraged him.

"It said, 'did I tell you your son begged for his life,' with a laughing face emoji," Guffey says. Law enforcement officials told him not to respond, but he says it took every ounce of strength he had to ignore it. He believes the scammers went through Gavin's friends list on social media and sent messages to everyone with a similar last name, including Guffey's nephew.

The family didn't have access to Gavin's computer and iPad -- investigators took them as part of the probe into his death, Guffey says. He started piecing together his son's final days using messages from the scammers and information shared by investigators. He discovered that the scammers used a vanish mode feature that deletes messages as soon as the recipient exits the chat.

"They used these disappearing messages. So the kids feel safe in the technology. What they don't realize is, someone has another device recording that device," he says.

Gavin had used Venmo to send the scammers $25 -- all the money he had in his account -- and pleaded for more time.

"He was telling them he would get them more money, please don't send these images out ... they didn't care," Guffey says. "I think in his mind it was just too much, and he didn't know how he would overcome that."

In an email to CNN, an FBI spokesperson in Columbia, South Carolina, said no arrests have been made in the case. It declined to provide additional information, citing an ongoing investigation.

Sextortion targets thousands of teens every year, the FBI says

Sextortion schemes happen primarily online.

In 2022, law enforcement agencies received over 7,000 reports related to the online sextortion of minors, federal officials say. Nearly half of those resulted in victims, a majority of them boys. Over a dozen of the sextortion victims died by suicide, the FBI says.

Predators typically trick their young male victims into believing they are talking to girls their own age, persuade them to send explicit photos and videos, and threaten to release those images if a payment is not sent.

Young people are more impulsive because they don't weigh risks and consequences the same way adults do, says Dr. Carl Fleisher, an expert in adolescent and child psychiatry, in an article on UCLA Health. Their judgment and decision-making abilities are underdeveloped because the prefrontal cortex — the brain's executive control center — is not fully developed until the mid-20s, Fleisher says.

"This crime starts when young people believe they are communicating with someone their own age who is interested in a relationship ..." the FBI says. "The shame, fear, and confusion children feel when they are caught in this cycle often prevents them from asking for help or reporting the abuse."

On its website, the FBI reminds teens that scammers prey on their fear. It urged them to report sextortions because they're not the ones committing a crime.

Sextortion scams have increasingly made headlines nationwide. But law enforcement is fighting back.

Mark Totten, a US attorney for the western district of Michigan, announced this month that three men will be extradited from Nigeria for allegedly extorting teenage boys. One of the men will be charged with causing the death of Jordan DeMay, 17, who died by suicide in March 2022 as a result of sextortion.

And in December police in Los Angeles arrested a suspect in the case of 17-year-old Ryan Last, who killed himself in February 2022 in San Jose, California, hours after being victimized by a similar sextortion scam.

Guffey's son was a free spirit who liked to prank his dad

Guffey knows all too well the emotional toll sextortion takes on families. Nearly a year later, he's still struggling with what happened at his home that morning.

He recalls cradling his son, thinking he'd fallen and hit his head while in the bathroom. He remembers catching a glimpse of his pistol on the floor, and smelling the gunpowder. He says he'll never forget his pain and confusion when he realized his son had died by suicide.

"I was a basket case, I didn't know what to do," he says. "My initial thought was, this is my fault -- I left the gun out."

Gavin loved skating and art, and had stickers of dinosaurs and his favorite characters -- Spider-Man and Deadpool -- plastered on his car's dashboard.

The day he died, a package addressed to him arrived in the mail. Gavin had ordered a flag with a face of rapper Ye -- formerly known as Kanye West -- against a backdrop of black and gold colors. It had the words, "Don't tread on Ye" on it.

Guffey chuckles at the memory.

"Gavin would constantly troll me. I'm a pretty conservative guy, and Gavin was more of a liberal kid," he says. "But I always encourage my kids to think on their own, and to be their own person. As long as they're thinking, that's what's most important."

The flag hangs in his office. It's a conversation starter that always leads to discussions about his son -- and the dangers that sextortion scams pose to teens.

Guffey describes sextortion as a lucrative crime that has attracted international fraudsters and local scammers alike.

"If you can extort 10 teenage boys that aren't gonna say anything for $100 each, and do all that with one image that you got from a girl, it's fairly simple," he says. "And teenage boys, whenever they see they're getting that attention (from a girl), they're not necessarily thinking."

He has a message to other teens: Tomorrow needs you

Guffey briefly considered quitting his role as a state representative to try and hunt down the scammers.

"My wife said, 'absolutely not. You're one of the few people that have a voice that can get out there and truly make a difference,' " he says. "And at that point, I had to decide: Is it more important to focus my effort into finding the individual that's responsible for my son's death? Or is it more important to spread the message and keep another family from having to feel this pain?"

He's made the latter a major part of his legislative platform. He's tattooed his son's last message on his left arm. Every time his fellow House legislators signed his bill, he gave them a lapel pin with a similar symbol.

On days when Guffey needed a boost of strength, he'd slip into Gavin's white Vans. The sneakers, scribbled with black lines and a Spider-Man doodle, made him feel like he could handle anything.

"I feel like he (Gavin) would want me trying to save additional kids from ever having to feel the way that he felt at that time," he says.

Guffey's goal, he says, is to make sextortion scammers think twice before they target children in South Carolina.

At Gavin's funeral, his friends put stickers of his favorite comic book characters on his casket. They also went to his favorite skate park and spray-painted a rock with a dinosaur and the <3 symbol, along with a message for other young people: "Tomorrow Needs You."

Guffey says he hopes teenagers will remember that message whenever they face challenges.