NEW YORK -- As he was arraigned on a charge of throwing his 5-month-old nephew to his death from the window of their Upper West Side apartment, Michael Holmes, an autistic teen-ager, saw his mother in the courtroom yesterday, her body sagging with grief, and he began wailing loudly, waving his arms and bobbing his head back and forth.
After Judge Michael A. Gross of Criminal Court ordered that the 17-year-old defendant be sent to Bellevue Hospital for a psychiatric examination, Michael's 18-year-old brother, Frederick, screamed: "You can't do this. He's my baby brother, please don't take him away!"
The sight of Michael Holmes rocking, suffering from a brain disorder that causes extreme introversion beginning in infancy and often results in a compulsive repetition of certain movements, raised a question of how a charge of second-degree murder would be handled by the criminal-justice system.
Barbara Thompson, a spokeswoman for the Manhattan district attorney's office, said it was an unusual case.
But most likely it will be submitted to a grand jury "because the indictment is a mechanism for initiating the legal process," she said.
"It doesn't mean jail or punishment," Ms. Thompson added. "It gives us and the court an option to deal with people who may have mental defects."
Norman Siegel, executive director of the New York Civil Liberties Union, said that under the law, an "affirmative defense" is one in which a person lacks criminal responsibility because of mental defects.
"You have to show that he lacks substantial capacity to know or appreciate the nature and the consequence of his conduct or that his conduct was wrong," Mr. Siegel said.
Michael Holmes' mother, Sally Holmes, said yesterday that her son was not a violent person and did not know what he was doing when he picked up the infant, Stanley Holmes, and dropped him from the fifth-floor window of their apartment Saturday.
An uncle who had been watching the baby had stepped away to answer the phone, police said.
"He didn't know what he was doing," she said. "Arresting him doesn't solve anything."