Joran Van der Sloot is in prison for murdering one woman and is a suspect in the disappearance of another -- Natalee Holloway. But Leidy Figueroa, who is pregnant with his child, plans to marry him. She isn't the first woman to knowingly wed a murderer.

Figueroa worked in the Peru jail where Van der Sloot is serving his term. She sold candies and cigarettes, but apparently her relationship with the convicted killer went further than the purchase of commissary goods.

Now, according to the Daily Mail, van der Sloot, 26, and Figueroa, 24, are set to get married on Friday at Lima's Pedras Gordas penitentiary in a midday ceremony. Their child is due in September, said Reuters.

Originally, reps for Van der Sloot denied the pregnancy. “It is not true that Joran got someone pregnant,” the convicted killer’s lawyer Aldo-Favio Cotrina told in an exclusive interview. “He doesn’t have any conjugal visitation, in order to get that you have to be married as it is only allowed with a wife,” he explained. Apparently the young man found a way around the rules. 

Van der Sloot landed behind bars after he confessed to killing 21-year-old business student Stephany Flores at a Lima casino in 2010. He was convicted two years later and sentenced to 28 years behind bars.

He also remains a suspect in the presumed death of 18-year-old Natalee Holloway in 2005; the Alabama teenager disappeared during a high school trip to Aruba. Van der Sloot has denied killing her, the Daily Mail said.

After his sentence is served in Peru, he will be extradited to the U.S. for questioning in the Holloway case, which remains open. Her body has never been found.

Although a murderer wouldn't seem like an attractive prospect for a relationship, Van der Sloot said the amount of love letters he received increased along with his notoriety. 

“If you are in a relationship with a man behind bars for life or a man on death row, then you have a lot of control over the relationship,” he reportedly said, according to the Daily Beast.

Part of what makes Van der Sloot attractive to women is his “celebrity,” Sheila Isenberg told the news site.

“We have always made media stars out of murderers,” she told the Daily Beast. “Anyone who gets noted in the media can become an object of hero worship. Then as a murderer he has the added notoriety. It makes him sexier to some people.”

Also, while celebrities are less likely to answer fan mail personally, prison inmates often write back. “Any guy sitting in jail or on death row will focus attention out of boredom,” she said. “But that romantic focus is like a blazing light to some women.”

Radford University forensic psychologist Mike Aamodt explained why some people like to associate with criminals.

"If you have a dull life, this gives you a purpose," Aamodt told "At parties, people ask who you're dating. If instead of saying that you're dating an accountant you can say you're dating a serial killer, doesn't that make you sound a lot more exciting?"

"You see it in junior high and high school," where the tough guys are the ones who win the hearts of the girls. "When you're talking about killers, that ups the bad-boy ante."

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