Hora and DuBois revealed the details of how Reiser, 44, killed Nina for the first time after he pleaded guilty to second-degree murder in April and was sentenced to 15 years to life Friday.

Hora and DuBois said that in a statement Reiser gave to authorities on Aug. 21 as part of the agreement that led to his second-degree murder plea today, Reiser said he got into a heated argument during a two-hour discussion the afternoon of Sept. 3, 2006.

The discussion took place on the middle level of Reiser's three-level house while the couple's children, Rory and Nio, played in the basement, the lawyers said.

DuBois said Nina "set him (Hans) off" by saying she would take the children to the doctor anytime she wanted to and he couldn't do anything about because she had custody.

Hans Reiser has repeatedly alleged that Nina was inventing illnesses in the children, particularly in Rory, as a way of getting back at him, DuBois said.

The defense lawyer said Reiser "snapped and took her life by strangulation." Reiser then put Nina's body in a duffel bag and took it up to a bathroom on the upper level.

That night, while the children slept, Hans put Nina's body inside his 1988 Honda Civic CRX and drove to an isolated area nearby, where he spent all night digging a grave. He didn't finish digging the grave the first night, so he went back the next night, finished digging the grave and buried Nina's body.

Hora said the Honda Civic CRX was a key focus in Reiser's trial, as its right front passenger seat was missing when police found it in the Oakland hills a short distance from his house, on Sept. 19, 2006, 16 days after Nina disappeared. Recalling that a neighbor testified that he saw Reiser thoroughly hosing off his car after Nina disappeared, Hora said Reiser did so because Nina's body was inside the car for two days.

In his statement on Aug. 21, Reiser said, "I got all of the blood out of the seat and I couldn't see any blood on the seat. Then I decided just to be paranoid and throw away the seat."

Reiser said Nina's comments to him on Sept. 3, 2006, "caused me to become enraged and, um, I killed her. And I shouldn't have. I'm very sorry that I did it."

Reiser, who took judo lessons for many years and had a black belt, said he placed his hands on both sides of Nina's neck.

"And in the most unsophisticated chokehold that any judo instructor would completely despise you for ever using, I choked her," said Reiser. "And this is the kind of choke that people who have no martial skills at all would employ and yet it was completely painless for her. It's the least painful way to die."

Reiser said his children were playing games downstairs and "never knew what happened."

Reiser said he cut his right hand when he punched Nina and still has a visible scar.

At the end of his statement, Reiser told Hora and his inspector, Bruce Brock, "You know, Nina was wonderful in so many ways. I'm so sorry."

He said, "I will regret for as long as I live what I did and I don't know how I could. ... I'm very sorry."

Reiser's case has received intense media coverage, including on the network news programs "48 Hours" and "ABC 20/20," and sound and light crews wired the courtroom of Alameda County Superior Court Judge Larry Goodman for Friday's hearing.

Nina Reiser, who was born in Russia, trained as a physician there and met Hans when he was doing business there.

She married Hans in 1999, but she separated from him in 2004 and was awarded legal custody of their two children. Nina was 31 at the time she disappeared.

Although Nina's body wasn't found despite a massive and heavily publicized search, Hans Reiser was prosecuted for her death based on circumstantial and blood evidence.

Hans Reiser, 44, spent 11 days on the witness stand denying that he had anything to do with Nina's disappearance, but at the end of his six-month trial on April 28 jurors convicted him of first-degree murder.

On July 7, Reiser led authorities to a remote spot near his house where he buried Nina's body and her remains were positively identified the next day.

In return for Reiser's post-verdict cooperation, prosecutor Paul Hora agreed to allow Reiser to plead guilty to the lesser charge of second-degree murder.

Reiser faced 25 years to life for first-degree murder.

This past Monday, prosecutor Paul Hora said in a brief hearing on the record that Reiser, 44, gave a statement regarding Nina's final day in a closed-door meeting in Goodman's courtroom last week.

Hora didn't disclose what Reiser said, but he said the transcript of Reiser's statement is 30 pages long.

Outside court, Hora said he doesn't want to say anything about what Reiser said until after Reiser is sentenced by Goodman on Friday.

"This is still in process and it's not over until it's over," Hora said. "It's not final."

Reiser was in Goodman's courtroom from 2 to 5 p.m. and frequently conferred with DuBois, both in court and in a stairway outside court. Reporters were kicked out of the courtroom after Reiser said he wanted to fire DuBois, something he has threatened to do on many previous occasions.

At a short open hearing that started at 4:47 p.m., Goodman said there were about two-hours worth of closed discussions today.

Outside court, DuBois said Reiser "tried to fire me for about the 15th time" but he's still Reiser's lawyer and will represent him at his sentencing on Friday.

DuBois said, "It's been a difficult case. In today's parlance, it's been very challenging."

Hans Reiser, who was born in Oakland and was admitted to the University of California, Berkeley, at the age of 16, met Nina in Russia, where she was born and was trained as a physician and where he often spent time doing business for his computer file system company.

In 1999 they moved to Oakland and were married, but she filed for divorce and separated from him in 2004. Although Nina was awarded legal custody of their two children, Hans had visitation rights.

The children moved to Russia in December 2006 to live with Nina's mother.