The young son of murder defendant Hans Reiser says he has no idea where his mother is.
Nina Reiser's body hasn't been found since she disappeared last year.
Attorneys for her estranged husband -- Hans -- have suggested
she may not be dead.
But prosecutors say they can prove that Nina -- who was involved in a better custody battle with her estranged husband -- say she was murdered.
Eight year-old Rory Reiser has been living in Russia with his maternal grandmother.
He returned to California to testify Tuesday.