Now, he faces criminal charges of attempted murder, burglary, strangulation and assault, and a civil suit from the woman.

The woman he is accused of choking, Pamela Robinson, of Asheville, N.C., describes a harrowing ordeal in the civil suit she filed seeking damages from Mr. Arzberger. Her lawsuit says that she answered the door of her room at the Hudson Hotel near Columbus Circle around 8 a.m. on March 27 and was confronted by Mr. Arzberger, who was “completely naked” and who pushed his way into her room, seized her by the throat and “violently shook her and threw her around, bashing her head into the walls and shelves of the hotel room closet.” It goes on to say that she was saved by hotel employees who entered her room and pulled him off her.

Mr. Arzberger declined to speak about what happened the night in question. In a court filing, prosecutors said that he had told the police after his arrest that he had visited a couple of bars and been awakened that morning by “the sound of a woman screaming for help” and had tried to comfort her but did not remember being in her room. His defense lawyers said they believed that he was drugged earlier that morning by a prostitute he had brought to his hotel room, who they later learned was a man. A criminal complaint was subsequently filed accusing a 34-year-old man of stealing three German credit cards from Mr. Arzberger’s hotel that night, but it did not name the victim of the theft.

Prosecutors have said in court that there was no evidence that Mr. Arzberger had been drugged. But one of his lawyers, Nicholas G. Kaizer, said: “The evidence will show that Arzberger was unquestionably the victim of a crime in the hours preceding the assault on this woman.” He continued, “The evidence also will show that there’s no other explanation, other than his being drugged, involuntarily drugged, for this conduct.”

Arriving for lunch at a restaurant north of Madison Square Park the other day, near the office of a forensic psychiatrist helping with his defense, Mr. Arzberger was carrying his violin, a backpack and the suitcase he has been living out of while staying with friends. He said he had come to the United States with the Leipzig Quartet on March 20 for a brief tour, including a concert at the Library of Congress, which he played, and one at the Harvard Club, which he missed while in police custody.