A software programmer was convicted Monday of first-degree murder for killing his estranged wife, who he contends may be living elsewhere.

Hans Reiser, 44, bowed his head in court as the jury found him guilty of a crime that carries a sentence of 25 years to life in prison.

Nina Reiser disappeared more than a year ago after dropping off the couple's children at Hans Reiser's home. Her body has never been found.

Reiser, known in programming circles as creator of the ReiserFS computer file system, testified for several days in the six-month trial, often giving rambling answers and getting scolded by the judge for arguing with the prosecutor.

Defense attorney William Du Bois said Monday he was disappointed with the verdict, but didn't think things would have gone differently if Reiser had never taken the stand.

Tom Orloff, the district attorney for Alameda County, said the verdict "does justice for Nina Reiser and her family."

Du Bois argued during the trial that there was no direct evidence linking his client to Nina Reiser's disappearance and suggested the woman may be living in her native Russia or may be the victim of foul play.

But prosecutors argued the circumstantial evidence against Reiser was strong: the two were involved in a bitter custody dispute, traces of her blood were found in his home and car and witnesses testified she would never have left her children.

Also, prosecutor Paul Hora said that after Nina Reiser disappeared, Reiser threw away the passenger seat of his car, hosed down the floorboards and started withdrawing large amounts of cash.

When Reiser was arrested in October 2006, he was carrying his passport and thousands of dollars.

Du Bois portrayed Reiser as eccentric, but nonviolent, and said there were innocent explanations for his behavior.

Reiser testified his wife left his house alive and he had nothing to do with her disappearance. He said he threw away the car seat to make the car more comfortable for sleeping in and washed the car floor because it was dirty.

Reiser said he drew out the cash to pay programmers at his company and was in the habit of carrying his passport as a frequent traveler.

Hora also said Reiser hated his estranged wife, and saw her as "the destroyer."

"She destroyed his marriage. She had an affair. He — although it was never proved — thinks she embezzled hundreds of thousands of dollars from him," Hora said during the trial.

Hora showed jurors a video of Nina Reiser at her son's 6th birthday party, ending with a freeze-frame of the mother kissing her son's cheek. He also played jurors a tape of an interview with Rory outside of court in which the prosecutor asked the boy if he knew where his mother was.

Rory said he didn't, and that made him feel sad.

"What did you like best about her?" Hora asked.

"Everything," said the boy.