Published: Jan 14, 2011 11:08 PM EST
Updated: Jan 14, 2011 8:12 PM EST

QUINCY, Mass. (AP) - A woman was arraigned in a Boston hospital bed Friday on accusations that she killed her 8-year-old son and tried to commit suicide by lighting a hibachi grill inside a bedroom in their apartment.

Li Rong Zhang remained hospitalized under guard after she was ordered held without bail on a murder charge.

Li was arrested one day after her 16-year-old son found her and another son, Brandon Young, unconscious in their home in Quincy, south of Boston, authorities said. Firefighters who broke through a barricaded door into a second-floor room found the younger boy lying on the bed and his 39-year-old mother on the floor Thursday afternoon, Norfolk District Attorney Michael Morrissey said.

 A preliminary autopsy was completed, and investigators were awaiting additional test results before ruling on a cause of death, Morrissey said.

"We don't have the medical examiner's report, but have sufficient evidence to at least bring charges against one individual," Morrissey said. "The investigation is ongoing."

 Investigators have determined that there were no problems with the heating in the apartment and there was no indication the hibachi grill was being used for heat, authorities said. It also didn't appear that anything was being cooked on the grill, Quincy Police Chief Paul Keenan said.

The poisonous carbon monoxide fumes from the grill were mostly confined in the barricaded bedroom and did not reach smoke detectors elsewhere in the apartment, Keenan said.

The woman's attorney, James Doyle, said a not-guilty plea was entered on her behalf. Li is grief-stricken in the intensive care unit, Doyle said before declining further comment.

A neighbor, Susan Sullivan, told WCVB-TV that she heard a fire alarm go off in the basement of the apartment building, but did not see or smell any smoke. She said she called the Quincy Housing Authority before leaving for work.

"When I pulled in after work, I saw the fire engine pull up, and then I saw them pull the little boy out," she told the TV station. She said she was "devastated" and wished she could have done something to prevent the death.

 In 2005, police responded to a report of a family disturbance, a verbal argument between Li and her husband, but no restraining order was obtained, Keenan said.

Morrissey said he did not know the woman's exact condition, "but when she is capable and able to be removed she will be taken to another secure facility."

She is due in Quincy District Court on Jan. 28.

(Copyright 2011 by The Associated Press. All Rights Reserved.)