“Greetings from New York, Chris!” a Brooklyn-based woman wrote to Christopher Watts on Aug. 23, days after he admitted to murdering his pregnant wife and young daughters, loading the bodies into his truck and dumping them at an oil work site.

“I found myself thinking a lot about you,” Tatiana confessed to the now-convicted killer.

The 29-year-old enclosed a bikini-clad photo of herself. “So you can place a face to the words. I know what you look like so I thought I’d make it fair,” she flirted. “I hope I’ve put a smile on your face.”

But if Tatiana failed, many others also aimed to cheer him up.

Watts was charged Aug. 20 with multiple counts of first-degree murder, unlawful termination of pregnancy and tampering with a deceased human body. He pleaded guilty. In November, a Colorado judge sentenced him to three consecutive life terms in prison — one for each murder victim.

In his six months behind bars, documents obtained from the prosecutor’s office by The Washington Post show, Tatiana’s was just one among many letters he received from hopeful suitors and fans.

Candace, a 39-year-old mother of two, wrote multiple times; her second letter ended with #TEAMCHRIS #LOVEHIM and a doodled heart. “I’ve been watching your interview and I just became attracted to you (don’t ask me why),” she said in one missive, adding that if he wrote back she would “be the happiest girl alive.”

Another woman named Christan began by “addressing the elephant in the room. No, I’m not a creeper or crazy.” She was drawn to Watts when she watched him take a deep breath as the judge read out his murder charges.

Tammy, 36, described herself as “a simple girl living in a small town” and included photos. She noted that it was her first time writing to an inmate and that she was “actually very nervous.”

The Ohio-based woman asked Watts, “Why is someone as pretty as me single? And writing to someone in jail?” (She recently came out of a bad breakup, she explained.)

How a woman could fall for a man jailed for killing his family might seem perplexing, but this decades-old phenomenon is far from unusual. Front-page offenders — like Jeffrey Dahmer, Ted Bundy, Charles Manson and the Menendez brothers — have also been pursued behind bars by countless women.

The incarcerated individual is likely to have become part of a fantasy for many of these women, given how popular true-crime shows are and how accessible the offenders are, Katherine Pier, a psychiatrist on the faculty at the University of California at San Francisco, told The Washington Post.

“It’s a way of flirting with danger while risking nothing,” said Pier, who has worked with felons. “The women writing killers are often victims of abuse and gravitate toward aggressors. Getting involved with a man behind bars puts them in positions of control. These women will most likely never have the chance to meet the man they’re pursuing. And if they did, they’d be protected by the prison system.”

Sheila Isenberg, author of “Women Who Love Men Who Kill,” echoed Pier.

Isenberg attributed the shift to the current celebrity-worshiping culture and the rise of social media platforms, which have “allowed for an explosion of female fans to come out of the woodwork.”

In the past, true-crime narratives making national headlines were reserved mostly for mass murderers. Now, serial-killer groupies have open communication forums. They generate Facebook groups and Reddit posts, giving notice to men who otherwise would have been little-known, garden-variety killers.

The more famous the person, the more magnetic he is.

“It makes domestic murderers like Watts public figures. They become notorious,” said Isenberg, who is working on a follow-up book, “More Women Who Love Men Who Kill.”