The first-degree murder case against a 19-year-old mother accused of placing her infant son in a microwave oven was forwarded to a New Kent County grand jury for a possible indictment, after the woman waived her right to a preliminary hearing today.

Elizabeth Renee Otte, who was accompanied by her parents, stood nearly motionless at a hearing in New Kent County General District Court as she answered questions from Judge James H. Smith with a softly spoken "Yes, sir." Otte did not comment otherwise during the hearing, and her attorney, Stephen Harris, declined to discuss the case afterward.

Smith ordered Otte to undergo by mid-January a psychiatric evaluation, which is intended to determine whether she is competent to stand trial and whether she was sane when she allegedly placed her 1-month-old son into the microwave in the early hours of Sept. 23. The baby, Joseph Lewis Martinez, died of thermal injuries that medical examiners have said are the type that can be caused by a microwave. Otte remains free on $20,000 bond and is living with her parents.

Officials want the medical evaluation of Otte to include neurological tests aimed at discovering whether Otte's epilepsy could have played a role in her alleged actions.

Otte's friends say the teenager said that she had an epileptic seizure that morning and doesn't remember what she did at the time prosecutors say she placed her son in the oven.

Though some experts have said it is possible that a particular type of epileptic seizure could have caused Otte to become temporarily confused and disoriented, others say that it would have been difficult for someone having a seizure to carry out the tasks of placing the child inside the oven and turning it on.

Commonwealth's Attorney C. Linwood Gregory affirmed his intent to prosecute, but he said he would wait to make a decision until the psychiatric evaluation is complete. He said the type of seizures Otte experiences--grand mal seizures--are usually debilitating and couldn't explain such an act.

Gregory said that the infant was shoved into an 18-inch microwave and that the oven was then programmed to turn on. He said the microwave was not equipped with any "one-button" settings that would have made turning the oven on a simple procedure, adding that it would have taken several distinct actions to start the oven.

"There is no doubt in my mind who put the baby in the microwave," Gregory said. "Malice is presumed by that act. Someone would have to know what would happen if they put a child in a microwave. But it is difficult to make any conclusions before the evaluation is made."

According to a medical examiner's report that has been made available to prosecutors, the baby died as a result of a series of "acute thermal injuries." The baby was found in the microwave in the morning by his aunt during a search of the house by relatives and sheriff's deputies for the infant after family members reported him missing.

Gregory said the case is the only known fatal microwave oven incident in the United States. Two cases in the 1980s resulted in two children receiving serious burns. In one case, a 1-month-old baby was placed in a microwave in Michigan and sustained burns "very similar" to those that killed Otte's baby, Gregory said.

CAPTION: Elizabeth Renee Otte, left, walks with her father, Larry Otte, at the New Kent County courthouse.