An ex-convict went on trial yesterday on charges of raping, torturing, and burning a Columbia University graduate student in a 19-hour attack during which her eyelids were slit and she was forced to ingest a massive dose of painkillers that caused liver failure.

Robert Williams, 31, sat with chained arms and legs, his head lowered, as the prosecutor delivered an opening statement that left several people in the courtroom weeping.

Williams violated the 23-year-old woman “in every way imaginable and in some ways unimaginable,” an assistant district attorney, Ann Prunty, told the jury, turning the victim’s small one-bedroom apartment into “his torture chamber.”

Ms. Prunty said Mr. Williams stopped the torture only after the victim — who at one point tried to kill herself to escape the ordeal — blacked out from hours of pain caused by knife wounds, boiling water, battering, and sexual assaults.

“Then he could no longer feel power over another human being,” Ms. Prunty said.

Mr. Williams is charged with kidnapping, arson, burglary, and sexual assault in the attack on the woman on April 13, 2007. He faces life in prison if convicted.

The defendant’s lawyer, Arnold Levine, tried but failed to have Mr. Williams declared mentally unfit for trial. Mr. Levine did not make an opening statement.

The victim, a Columbia University journalism graduate student, found Mr. Williams in her building’s elevator in the Hamilton Heights neighborhood of Upper Manhattan when she came home around 9:30 p.m., Ms. Prunty said. She said he followed her to her fifth-floor apartment and began his rampage.

Williams raped and sodomized the victim and forced her to perform oral sex several times, the prosecutor said, then poured boiling water all over her to try to remove evidence. He also cut her long hair during the assaults because it got in the way, Ms. Prunty said.

After one assault, he forced the woman to swallow a fistful of pills from her medicine cabinet and wash them down with four beers, Ms. Prunty said.

Doctors later said the woman’s liver had failed, probably because of the medicine, and that a liver transplant might be necessary. Fortunately, the transplant was not needed, Ms. Prunty said.

After about 19 hours, Ms. Prunty said, Mr. Williams tied the naked, unconscious woman to a futon with computer cables and set it afire. The woman awoke and smelled smoke, broke free, and made her way to the hallway, where she was rescued.

Ms. Prunty said Mr. Williams’ DNA was found on the victim and her clothing, and her DNA was found on his clothing. ATM security cameras captured him trying to withdraw the money, she said.

During the time she was conscious, Ms. Prunty said, the victim studied Williams closely. Ms. Prunty said every scar and feature she later described to police matched the appearance of the defendant.