The world was introduced to Chris Watts, a 33-year-old oil field operator in Colorado, on local television. Tanned and fit, he looked into the camera ― apparently in anguish ― and begged for his family to come home.

His pregnant wife and their two daughters had vanished.

Within a day, he was in handcuffs. Police found his wife, Shanann Watts, 34, buried in a shallow grave at an oil field owned by his employer. Floating in nearby oil tanks were his daughters, Bella, 4, and Celeste, 3.

Domestic violence killings are common and rarely get sustained national media attention. But this case was different. It had all the ingredients for a tabloid sensation. A pretty mom who documented her every move on social media. A disappearance. A pregnancy. And a vicious, inexplicable crime.

It didn’t hurt that the family was young, white and Instagram perfect.

Chris Watts eventually admitted to all three murders and was sentenced to life behind bars. Once the case was over, the district attorney released thousands of pages of documents related to the deaths in response to a Freedom of Information Act request. Much of it was standard ― photos of the crime scenes, interviews with witnesses, copies of text messages.

But nestled among the documents was something unusual: a cache of adoring letters sent to Watts while he sat in jail awaiting trial. To some women observing from afar, Watts was a heartthrob ― and a potential romantic interest.

“I want to get to know you soooo bad its not even funny,” a 39-year-old woman from Colorado wrote to him. “Literally your on my mind almost every single day since you were in the news.” In a follow-up note, she said she would be “the happiest girl alive” if Watts wrote her back. She signed off with the hashtags #TEAMCHRIS, #CHRISISINNOCENT, #LOVEHIM and #SOOOOCUTE.

On its face, it’s difficult to comprehend why any woman would fall for a man known solely for committing a violent crime. Especially the vicious killing of his own family. And yet they do.

Attracted To Notoriety

The phenomenon of women becoming infatuated with murderers behind bars is not new: Notorious killers throughout history, like Ted Bundy and John Wayne Gacy, attracted female groupies. Charles Manson was engaged to a woman who began writing to him in prison when she was a teen.

Recently, the accused Parkland, Florida, school shooter, Nikolas Cruz, has been inundated with love letters. So has Steven Avery, the subject of the hit documentary series “Making a Murderer,” who was convicted of killing Teresa Halbach. Just this week, a woman who exchanged letters with Dylann Roof, a white supremacist who massacred nine black worshippers at a church in 2015, was arrested for plotting to attack a bar.

But experts reached by HuffPost said that cases appear to be increasing, because of the public’s fascination with true crime and the rise of social media.

“We have always worshipped our celebrities,” said Sheila Isenberg, who interviewed women obsessed with murderers for her book Women Who Love Men Who Kill. “In the past, it was just movie stars. Now anybody who does anything unique becomes a celebrity, even if they’ve committed murder.”

Nowhere is this more apparent than on Facebook, where true crime groupies gather to discuss cases. One such page, dedicated to the Watts murders, has over 19,000 members. In a recent thread, members debated whether Ryan Gosling or Jake Gyllenhaal should play Watts in a movie.

“People can communicate with each other instantly to discuss the case, and they can make heroes out of criminals,” Isenberg said. “Today more than ever, this is a common phenomenon.”

Facebook Chris and Shanann Watts with their two daughters, Celeste and Bella. He is serving a life sentence without parole for murdering his family.

In handwritten letters to Watts released by the state, some illustrated with hearts, many women described feeling inexplicably drawn to him after hearing about his case. A few said they believed his claims that he didn’t kill his kids ― he originally told police his wife murdered them ― while others said they didn’t care what happened and wouldn’t ask him details.

“I know I’m a stranger ― but I care about you and your situation. I can’t help it. Is there anything you need? Can I send you something ― a book perhaps?” wrote a 29-year-old Brooklyn woman in a tidy script on lined notebook paper. “Keep your head up and stay strong. Please know there are strangers out there (like me) who care about you.”

She enclosed a photo of herself in a bikini.

“I will never ask you anything about your case,” wrote another woman, a 39-year-old who said she was currently incarcerated for a financial crime. “For some reason I find myself caring about how you’re doing. So all I’m trying to say is that I’m here.”

Women who are besotted with murderers often remain in denial about the crime. That way they can live inside a fantasy relationship, experts told HuffPost. There is a bizarre juxtaposition between the affectionate mood of the letters to Watts and the gruesome facts of his case.

Autopsy reports revealed that Watts slowly killed his wife by strangulation, which would have taken two to four minutes, according to prosecutors. He suffocated his two daughters to death. Bella, who was 4, had bite marks on her tongue and cuts in her mouth, indicating that she fought for her life.

Investigators believe Chris Watts killed his family because he was having an affair and wanted a new start without the baggage of a pregnant wife and two young children. In the weeks leading up to the murders, Shanann Watts, sensing his distance, tried desperately to fix their marriage, even sending her husband a book titled Hold Me Tight: Seven Conversations for a Lifetime of Love.

Police found the apparently unread book in the trash.

Understanding Why

There are many reasons women are attracted to men locked up for monstrous crimes. Some are motivated by a desire for fame, Isenberg explained. They want to be in the spotlight and believe that having a relationship with a high-profile killer could translate to a television interview or book deal.

“They don’t look at the crime. They look at his fame, and they don’t even do it on a conscious level,” she said. “They think that by being associated with him, they can get their names in the papers too.”

Katherine Ramsland, a forensic psychology professor at DeSales University, said that in rare cases, women may be sexually aroused by the idea that the men committed a violent act, a condition called hybristophilia.

“There is a titillation factor of getting close to violence,” she said.

More commonly, though, she said, women are motivated by an instinct to nurture. They think ― however naively ― that they can fix such men with their love. They want to tame them.

“It empowers the woman to believe that she, unlike anyone else out there, can create this special relationship that will change this guy and redeem him,” she said.

In letter after letter, many women encouraged Chris Watts to keep his head high and expressed concern about his state of mind. Some divulged personal details about their lives, describing their day-to-day activities and interests, like their favorite sports teams. Others wrote to him offering him emotional support.

“You honestly have one of the kindest faces I’ve ever seen,” wrote a 35-year-old woman from Australia. “I don’t even know you, yet I don’t want you to feel alone.”

California psychiatrist Carole Lieberman, who wrote Bad Boys: Why We Love Them, How to Live With Them and When to Leave Them, said in her experience, many women who reach out to men in prison have low self-esteem.

In some cases, she said, women may have experienced abuse in the past.

“They feel unlovable,” she said. “They don’t feel they deserve a man who has more to offer them, and so they go for this special kind of relationship with a murderer.”