D.C. public health officials said yesterday that Emory Lee, a 21-year-old mentally retarded man found dead Jan. 18 in a hot, locked seclusion room at St. Elizabeths Hospital, died of a seizure linked to his poor medical condition.

Public Health Commissioner Andrew McBride said external factors, such as the temperature of the room and possible stress of seclusion, did not contribute to Lee's death. McBride based his comments on the findings of an autopsy and investigation conducted by the D.C. medical examiner's office, which determined that Lee died of "an unspecified seizure disorder."

McBride said the investigation was "very thorough" and that he was "satisfied" with the result.

But Alan Steele-Nicholson, an attorney for Lee's mother, said the medical examiner's finding "doesn't alter the fact that Emory Lee was locked in an insufferably hot room for two days. I think there remain some very serious unanswered questions about why he died and what kind of treatment he received."

D.C. Del. Walter E. Fauntroy, whose office has been conducting its own inquiry into Lee's death, said in a statement that "while we are satisfied that the immediate cause of death was due to natural circumstances," he has questions about the hospital's actions. Fauntroy has scheduled a congressional hearing on Lee's case April 15.

Staff at the federally run mental hospital placed Lee in a seclusion room to control his behavior. Hospital officials have acknowledged that the room was very warm as the result of unseasonably hot weather and a malfunctioning heating system.

Although the temperature of the room has not been determined, McBride said heat was not a factor in Lee's death and the seizure disorder was related to Lee's Downs syndrome and severe retardation.

McBride said the death certificate also noted that Lee was being treated with a potent tranquilizer that can lead to a neurological disorder. McBride said such a disorder could have caused the rigidity and 106 degree temperature of Lee's body after his death.

McBride said Lee's enlarged heart and severe obesity also contributed to his death.