A computer genius, his Russian bride, the KGB, intrigue and murder

This story was previously broadcast on Jan. 3, 2008. It was updated on July 18, 2009.

California computer whiz Hans Reiser seemed to have it all - including a beautiful Russian wife, who was a doctor, and two children. That perfect life hit turbulence when his wife, Nina, had an affair with one of his best friends. Hans and Nina eventually separated and got into a bitter custody fight.

Fast forward to Labor Day weekend 2006, when Nina dropped the children off at their father's house, and mysteriously vanished in the hours that followed.

What happened to Nina Reiser?

Correspondent Maureen Maher reports on the twisted case involving a computer genius, foreign intrigue, and a best friend's betrayal.

Sean Sturgeon knew Hans and Nina Reiser better than almost anyone, and he had a particular fondness for Nina.

Asked what he loved most about her, Sean tells correspondent Maureen Maher, "That she got excited, she'd jump up and down like a pogo stick. She wanted to taste the world, she wanted to grow. I love that she loved life."

The last time he spoke to her, it was about some money he had left in her mailbox. "Called her up and said, 'Honey, there's some money there. I know you need it.' She said, 'Sean, I don't know when I can pay you back.' That was the last time I saw her," he remembers.

That was the same weekend Nina was making plans with her good friend, Ellen Doren. "Sunday morning she called and she said 'Why don't we have dinner together? I can bring dinner to your house,'" Ellen remembers.

Nina and Ellen are both Russian and they both had American husbands. Ellen says Nina often spoke of her husband, Hans.

Theirs was a relationship that began half a world away from Oakland.

It was back in the 1990s in St. Petersburg, long known as Russia's window to the west, where Nina, an obstetrician, and Hans, a computer wizard, first met. They had very little in common, but the quirky American managed to make the young, beautiful doctor look twice. Once smitten, the two quickly became serious.

Hans was one of the visionaries behind the Linux computer operating system and was in Russia looking for cheap programmers for his new software company.

Josh Davis, a writer for Wired magazine and a 48 Hours consultant, says Hans was developing an expertise in something called "file systems."

"It's one of the most basic parts of a computer. Hans felt very passionate that this was what he was going to make his life's work," Davis says.

His life's work, it turned out, included having a Russian wife, says best friend Sean Sturgeon. "There was the Hans flow chart, and the Hans flow chart was pretty, you know, basic. He said to me, 'I want a beautiful, well-educated, professional woman to give up everything to have my children and raise them.'"

Hans thought he'd found what he was looking for when he spotted a photo of Nina in a Russian bride magazine.

Asked if she truly fell in love with Hans, Sean says, "I think that she loved him."