OAKLAND -- The mother of Nina Reiser testified Wednesday that Nina wasn't the type of person who would have disappeared on her own or abandoned her two children.

In her second day on the witness stand in the trial of Oakland computer engineer Hans Reiser on charges that he murdered Nina, who was last seen alive on Sept. 3, 2006, Irina Sharanova said she hasn't seen her daughter since July of 2006, when Nina visited Russia, or had any communication with her since she disappeared.

Prosecutor Paul Hora asked her, "Based on spending your entire life knowing Nina, was she the type of daughter who would do that to you? Just disappear and not contact you or call you?"

Fighting back tears, Sharanova said, "No. That would have been impossible."

Hora asked, "Would she have been the type of mother who would have left her kids up for grabs and abandoned them?"

Sharanova said Nina wouldn't have done that.

Nina Reiser, who was 31 at the time, was last seen alive on Sept. 3, 2006, when she dropped off the couple's children at Hans Reiser's home at 6979 Exeter Drive in the Oakland hills.

Her body has never been found, despite extensive searches in the Oakland hills and elsewhere, but Hans Reiser was charged with murdering her because prosecutors believe that DNA and blood evidence proves that he killed her.

Hans and Nina Reiser married in 1999 but Nina filed for divorce and separated from him in 2004. They were in the midst of an acrimonious divorce and a battle over the custody of their children when she disappeared.

Hans Reiser has pleaded not guilty to the charges against him.

Hora's questioning of Sharanova seemed to be aimed at contradicting speculation by Hans Reiser's attorney, William DuBois, that Nina Reiser may still be alive and be in hiding in Russia, where she was raised and was trained as a doctor.

Sharanova, 59, said she fought for custody of the couple's children after Nina disappeared because she believes Hans Reiser killed her daughter.

She said she didn't want the children "to be with a killer."

Sharanova currently has custody of the children at her home in St. Petersburg, Russia.

Sharanova said the couple's son, Rory, didn't sleep well after Nina disappeared.

She said, "He very often talked about his mother and we began to think that he was conducting his own investigation."

Sharanova said Rory "very often was asking who's looking for her (Nina) and how they will find her."

Sharanova verified that she sent an email to Hora last May 16 saying she asked Rory about a fight that Nina and Hans had on the day that Nina disappeared.

In the email, Sharanova said, "He (Rory) said that they (Hans and Nina) often had fights."

Sharanova said in the email that she also asked Rory "about the scarf."

In court Wednesday, she said Rory recalled an incident in which Nina "couldn't scream because Hans covered her mouth with a scarf."

In the email, Sharanova said Rory also told her there was a room in Hans Reiser's house that "no one ever entered" and it was adjacent to the room where the children slept when they stayed with him.

Sharanova said Rory told her "if Hans hid Nina, he would have hidden her in that room."

DuBois began cross-examining Sharanova in the late afternoon and will continue his cross-examination when Reiser's trial resumes Thursday morning.

Sharanova is the prosecution's last witness in the lengthy case, which began on Nov. 6. DuBois might start presenting the defense's case sometime on Thursday, but most likely won't start until Tuesday, following a long weekend for the President's Day holiday.

DuBois hasn't yet decided if Reiser will testify in his own defense.