In September 2006, Nina Reiser, a 31-year-old doctor and mother of two, disappeared.
Nina and her husband, Hans Reiser, were in the midst of a nasty divorce, and even without a body, it didn't take long for police to arrest Reiser and charge him with his wife's murder. Recently Reiser sat down with "20/20" in an exclusive pretrial jailhouse interview.
Asked if he thinks that Nina is alive today, Reiser said, "I think I'm a person who doesn't know."
Reiser was a child prodigy who dropped out of junior high school and enrolled at the University of California Berkeley at age 15. After college, he made his mark in the business world, starting a technology company and developing a new computer file system some consider revolutionary.
So how did a self-described "computer nerd" capture the heart of a beautiful obstetrician born in Russia? Reiser went to Russia looking for cheap labor for his computer business, and a bride. A dating service arranged a meeting at a café in St. Petersburg, but Reiser didn't fall for his date -- he liked the woman who came along to translate.
"She has the most beautiful voice," Reiser said. "When I first heard it I thought, 'This is someone special.'"
Just over a year later, Reiser married his Russian bride, who was by then five months pregnant. A bizarre wedding video shows a nontraditional wedding -- Reiser's best friend Sean Sturgeon, dressed in drag, was the maid of honor.
"I think that what interested [Nina] in Hans was that he was different from everyone else," said her friend Ellen Doren.
"Nina is entirely unique," Reiser said. "Try to imagine a well-educated Marilyn Monroe, who's a doctor."
The birth of their son Rory, now 8, and daughter Niroline, now 6, were happy times for the couple. "Nina was one of the best parents I've seen in my life," Doren said.
Reiser, who lost custody of his children in the divorce proceedings before his wife's disappearance, said, "I miss them so much. It's been so long."
But fights about how those children were being raised were at the center of a marriage that began to crumble. Doren said she was witness to the emotional disputes.
"They just could not agree on how to raise the kids," she said. "And there were very many, many fights and conflicts."
Reiser, whose work kept him overseas in Russia for months at a time, wanted more children and did not want Nina returning to work as a doctor.
"I ran the business and I expected my wife to take care of the kids," he said.
Reiser said he was "a bit naïve" when it came to his wife.
"The objective evidence doesn't support what I believed at the time. She divorced me the day she became a citizen. I don't know whether it was the exact day but same month -- close enough," he said.
Reiser also said that Nina, who ran the finances for the family computer business, was embezzling money.
Ramone Reiser, Reiser's father, believes "there's no question" Nina purposely got pregnant before the marriage.
"I have yet to get him to admit how much Nina was cleaning out the money," said Ramone Reiser. "He needs to stop thinking that something happened to her, or whatever. She took off and left him."
"The fact that she was gone wasn't a great surprise to Hans," said his attorney, William Dubois. "What came down on him like a ton of bricks was the fact that the police suspected foul play, and he was the primary suspect."
When asked if there were other factors that contributed to the division in their marriage, Reiser replied, "Well, she slept with my best friend."
Hans believes that his childhood friend Sturgeon introduced his wife to drugs and exotic sex in a twisted act of revenge.
"He offered to have a relationship with me and I said no, cause I'm just not gay," said Reiser. "He was jealous, and then later he saw me and Nina having this family, and I think he saw it as something that he couldn't have. … When people feel rejected they do crazy things."
Doren sees the relationship between Sturgeon and Nina differently.
"When Hans went to Russia, he presented Sean to Nina saying, 'This is my best friend. He's here to take care of you. Whatever you need, go ask Sean,'" said Doren, adding that she never worried that Sturgeon was involved in Nina's disappearance. "He loved her dearly," she said.
Sturgeon won't talk publicly until after the trial, but after Nina's disappearance he made a bold confession to police, so outrageous that the judge won't allow it to be mentioned in court. He claims to be a serial killer, but said he is not responsible for Nina's death.
The morning of her disappearance, Nina took her two children grocery shopping and then headed to her mother-in-law's house, where Reiser was to take the kids for the rest of the Labor Day weekend. Nina had plans to spend the evening with her best friend.
"She was supposed to be at my house at 6:30, and I started to get worried at 6:35," said Doren. "'Cause she was never late, and then not to call was very, very unusual."
Doren called Nina's cell phone every half an hour through the night, and by Monday morning she was panicked. Doren said that on Tuesday, before anyone knew for sure that Nina was missing, Reiser made a rare appearance at the children's school and told the school to get in touch with him in case of trouble.
"That was very unusual for him, to go to the school," said Doren. "And especially to leave his cell phone number as an emergency contact. Nina normally took care of that."
When the police attempted to question him, Reiser tried to evade them, once even jumping out of his car and running for blocks. His attorneys didn't want him talking about the evidence against him before trial, but his father said he may be to blame for some of his son's strange behavior. He told Reiser it might not be the police who were tailing him at all, but perhaps someone more sinister connected with Nina.
"I said, 'If people are following you, either they identify themselves who they are legitimately or you don't let them follow you,'" said Ramone Reiser.
"20/20" traveled to St. Petersburg, Russia, to meet Nina's family. Her mother, Irina Sharanova, said her daughter just fell in love with the wrong man.
"[Hans] often screamed at her," she said. "If she spoke on the phone, if she was walking with children, if she was talking with us on the phone. He was always angry with her."
When asked if Nina was fearful, Sharanova said, "Yes, that's right."
Before Nina's disappearance, she accused Reiser of pushing her down and was granted a restraining order against him.
"I told her to be afraid of him," said Doren.
"Two weeks after Nina disappeared, I tried to get in touch with Hans, I tried phoning him," Sharanova said. "Not even a single time he answered my calls. I think if a man is not involved into something horrible, he will not be behaving this way."
As for claims that Nina was a gold digger, anxious to flee to America, both Sharanova and Doren say nothing could be more ridiculous.
"Nina's family is a very successful family of doctors," said Doren. "She's a third generation doctor. They have a beautiful apartment in the middle of St. Petersburg. They've always had cars and a country house."
Sharanova believes that her daughter is dead and dismisses the suggestion that she disappeared to start a new life. "She would be with her children," she said.
"I feel we don't have closure until there is justice," said Doren at a memorial service held to mark the one year anniversary of Nina's disappearance. "She is the most caring and giving person I have ever met in my life, and she deserved so much more in her life."
The direct physical evidence against Reiser is limited, but police have built a detailed circumstantial case. When police arrested him the floors of his car were wet and the passenger seat was missing. Reiser claims that because he was a suspect, the authorities would not allow his mother to take custody of his children unless he moved out, so he had been living out of his car.
"He had to vacate the premises," said Dubois. "And so he finds himself living in his car. Which, for him, seemed the logical thing to do under the circumstances."
When Reiser was picked up for DNA testing, he was carrying his passport and nearly $9,000 in cash.
"It's nothing sinister. Actually it has to do with payment of his employees in Russia," said his father.
In his car police found two books on murder investigations, purchased five days after Nina's disappearance.
"He's that type of person who would try to inform himself on the subject of police investigations once he found he was the target of one," said his attorney Dubois.
Reiser writes relentlessly to his children, who are now living with their grandmother in Russia. But according to those who have read the letters, he never mentions the mother of his children … his missing wife.
"The kids are writing back to him, but every letter has a question: Where's our mom?" said Doren.
"All my relatives, my husband and my kids, we would like to ask only one thing: Where is Nina?" said Sharanova.