A Letter of Warning Is Among Items Found in Suspect’s Home : FBI raid: A canister of plaster of Paris and a book on electronic devices were also in Fares Khallafalla’s New Jersey apartment.

By Thursday afternoon, Fares Khallafalla was gone, arrested by the FBI, but signs of his life in America were strewn about his second-story apartment here just across the Hudson River from New York’s World Trade Center.

There were several books, including the Koran and a copy of “Electronic Devices and Circuit History, Third Edition.” On a chair lay flyers from the National Rifle Assn., outlining “gun safety rules.”

A blue and gold poster, tacked to the wall above his bed, displayed a Middle East sunset and implored: “Save Jerusalem.”

The FBI left behind a document on the kitchen table that noted a four-pound canister of plaster of Paris had been seized that morning.

Also in the apartment was a two-page letter sent by defense attorney William Kunstler, warning that FBI agents had been spotted asking questions and seeking information in the New York area. The letter advised readers that if the FBI appeared at their door, they should say nothing, offer nothing and call Kunstler’s office immediately.

“The FBI is in town,” the letter said. “They might want to talk to you.”

Kunstler, a 73-year-old attorney who has made a career of representing radical causes, was the lawyer for El Sayyid A. Nosair, who was tried in the assassination of Rabbi Meir Kahane, founder of the militant Jewish Defense League. Nosair was acquitted of murder but convicted of lesser charges and is serving a 22-year prison sentence. He has been linked to several defendants in February’s car bombing of the World Trade Center.

At 1 a.m. Thursday, the FBI did more than just talk.

In a series of raids, federal agents arrested eight men, including Khallafalla, 31, and accused them of plotting a series of bombings in the wake of the trade center blast that left six people dead and more than 1,000 injured.

The government alleged that the men were preparing to attack a number of targets, including the United Nations building; the Lincoln and Holland tunnels, which carry commuters in and out of New York; and Sen. Alfonse M. D’Amato (R-N.Y.).

Officials suggested that the men had ties to Sheik Omar Abdul Rahman, a radical Muslim cleric who allegedly served as the spiritual leader of several men awaiting trial in the trade center bombing.

FBI and local police surrounded Abdul Rahman’s apartment in Jersey City for hours Thursday, cordoning off the street. Officials would say only that they were searching Apartment 48, the 55-year-old blind cleric’s home, but had not issued a warrant for his arrest.

About 5:15 p.m., law enforcement personnel left, taking with them two boxes of items.

Abdul Rahman often led prayer services inside the $550-a-month apartment or at a storefront converted into a mosque in downtown Jersey City.

Robert Rivera, son of the apartment superintendent, said the mullah is seldom seen without bodyguards. Abdul Rahman is always escorted in and out of the brown brick building.

There is no furniture inside Abdul Rahman’s apartment. Instead, visitors sit on mats on the floor. Likewise, there are no pictures on the wall except for several printed verses from the Koran.

“It’s not unusual to see them gathering there,” Rivera said. “They all look up to him like a high figure.”

A half-mile away is Khallafalla’s two-bedroom apartment. The door outside had been broken by the FBI and the lock on Apartment 4 had been ripped open. Moataz Adam, a longtime friend of Khallafalla’s who lives in an apartment below, was sticking gray tape over the door to keep it shut.

Adam said that Khallafalla came to the United States from Sudan about five years ago and took a job with International Service System Inc., a medical delivery company. Single and with his family back in Sudan, Khallafalla sent much of his money home to help his relatives, Adam said.

“He was a nice guy,” he said. “He was a cool guy.”

Adam was awakened in the middle of the night as the FBI burst inside the apartment building. He said that he dressed quickly and tried to help his friend but “a lot of the cops held me and told me to stay away.”

“I am really surprised,” Adam added. “There are a lot of people from Sudan coming over here to make money and he was one of them. But he would never hurt anybody.”

However, another apartment building resident, Maria Aresa, who immigrated here two decades ago from Guatemala, said she has been worrying for months about Khallafalla and a group of his friends who always met late at night upstairs.

“I knew something was wrong because every night different men came and I didn’t want them here,” she said. “There were eight men and everybody seemed to have a beautiful new car. They would park out front and every time I could hear them going upstairs, arguing and yelling.”

She was awakened again Thursday morning, but this time it was the FBI thundering up the steps.