A Moroccan man being tried in Germany on charges of aiding in the Sept. 11, 2001, plot said in court today that he was shocked by the attacks and found it unbearable to be confronted during the proceedings by relatives of the dead who believe he was an accessory to mass murder.

"Their testimony affected me like everyone else, and they looked at me as if I was responsible," said Mounir Motassadeq, 28, an engineering student accused of more than 3,000 counts of accessory to murder, as well as membership in a terrorist organization. "I was shocked when I saw the pictures. I could hardly understand that people I knew had done this."

Addressing a panel of judges as part of the defense's closing statements, Motassadeq appealed for a verdict of not guilty in the trial, which included dramatic testimony from relatives of people who were killed in the attacks.

Attorneys for the defendant, who is the first person to go on trial for involvement in the attacks, also addressed the court. They argued that the prosecution constructed a flawed case based on dubious witness testimony about the defendant's beliefs and construed his friendship with some of the hijackers as participation in the conspiracy.

"What we have seen here is suspicions, interpretations of behavior and interpretations of beliefs," one attorney, Hans Leistritz, said in the Hamburg courtroom. "After September 11, everything that had anything to do with the Arab world or with Muslims was suspect."

Leistritz said Motassadeq had done little more than befriend fellow Muslims and help them out, including assuming power of attorney over the bank account of one of the hijackers, Marwan Al-Shehhi, who piloted the second plane to hit the World Trade Center.

Motassadeq has acknowledged going to a camp in Afghanistan run by the al Qaeda terrorist network, but another defense attorney said that did not prove his client was a violent extremist. When he was questioned by police after the attacks, Motassadeq at first denied ever having been to Afghanistan. But on the opening day of the trial Oct. 22, Motassadeq acknowledged attending a camp there.

"He simply was afraid of the questioning," Hartmut Jacobi, a second defense attorney, told the judges. "When you are in a foreign culture, you often make mistakes and try to talk your way out of them. . . . There are thousands of young Arab men who have completed such training."

The defense also said that the trial was fundamentally unfair because the U.S. and German governments had held back material from the interrogation of Ramzi Binalshibh, the self-described coordinator of the plot who was captured in Pakistan on the first anniversary of the attacks and turned over to the CIA.

"It is a political move, and it has denied the defendant important material," said Jacobi, in a final protest.

The judges, and appeals courts, dismissed attempts by Motassadeq's attorneys to have the trial suspended or dismissed on the grounds that the lack of testimony from Binalshibh rendered it unfair.

Prosecutors have demanded the maximum sentence of 15 years, arguing last week that Motassadeq was aware of the hijackers' plans and provided logistical backup, including money transfers.

Special correspondent Souad Mekhennet in Hamburg contributed to this report.

Mounir Motassadeq, accused of more than 3,000 counts of accessory to murder, says the Sept. 11, 2001, attacks left him stunned.