An 84-year-old New Jersey man is facing federal criminal charges that a quarter-century ago he passed along secret Army documents concerning nuclear weaponry to the Israeli consulate in Manhattan, an act of espionage that prosecutors say is connected to the case of the most famous American spy for Israel, Jonathan Pollard.

A criminal complaint filed yesterday against the man, Ben-Ami Kadish, offers no clues about when law enforcement officials first learned of the alleged spying or what prompted them to investigate the case at this late date. Yet FBI agents managed to get a confession out of Mr. Kadish last month, the complaint claims. A former Justice Department official who has investigated Israeli spying told The New York Sun that he believes the government’s investigation of Mr. Kadish’s arrest was likely triggered by a wiretap of a former Israeli consular official, Yosef Yagur, who allegedly served as Mr. Kadish’s handler. Mr. Yagur fled America in 1985 at the time of the arrest of an American naval analyst, Pollard, who spied for Israel in the early 1980s, during the same period of time that Mr. Kadish allegedly spied. Both Pollard and Mr. Kadish reported to the same Israeli official: Mr. Yagur, according to information in the complaint.

Mr. Kadish apparently stayed in touch with Mr. Yagur in the intervening years, according to the complaint. Mr. Kadish traveled to Israel in 2004 and met with Mr. Yagur there, the complaint said.

“I think they found Kadish through Yagur,” the former Justice Department official, Joseph diGenova, who investigated and prosecuted Pollard, speculated. “That’s the only way that makes much sense.”

The complaint indicates that law enforcement has intercepted phone conversations between Mr. Kadish and Mr. Yagur, although no information about a wiretap warrant was publicly available.

In his long life Mr. Kadish has served in three militaries: he fought with the Jewish Haganah as well as with British and American militaries during World War II, according to a profile of him in the New Jersey Jewish News in 2006. He grew up in British mandatory Palestine, according to the article, which said he was active in the Jewish Federation of Greater Middlesex County and the Jewish War Veterans. Prosecutors say he was born in Connecticut.

Leaving from his arraignment in U.S. District Court in Manhattan yesterday, Mr. Kadish walked briskly by a throng of reporters without commenting and left in a banged-up Chevrolet Monte Carlo.

Mr. Kadish has admitted to the FBI that when he worked at an Army arsenal, he did pass along national security documents to Mr. Yagur, an FBI agent working the case, Lance Ashworth, claims in the complaint.

The complaint said that Mr. Kadish told agents in their first interview, which occurred late last month, that he “believed that providing classified documents to CC-1 would help Israel,” referring to the co-conspirator. The complaint does not identify the co-conspirator by name, but Mr. diGenova said corroborating information in the complaint indicates that the co-conspirator is Mr. Yagur, who served as the consul for science affairs at the Israeli consulate in Manhattan.

As a mechanical engineer at the Army’s Armament Research, Development, and Engineering Center at the Picatinny Arsenal in Dover, New Jersey, Mr. Kadish had access to classified documents, the complaint said. Library records from 1979 to 1985 indicate that Mr. Kadish checked out at least 35 documents including one “concerning nuclear weaponry,” and another that dealt with the U.S. Patriot missile air defense system, the complaint said, adding that some of the information was classified above Mr. Kadish’s “Secret” level of clearance.

In a March 20 interview with Agent Ashworth, Mr. Kadish said he would take the documents by briefcase to his home in New Jersey, where Mr. Yagur would come to photograph them in his basement, according to the complaint. He says that he met Mr. Yagur, his handler, through his brother in the 1970s. Both Mr. Kadish’s brother and Mr. Yagur were then colleagues for the company now known as Israeli Aerospace Industries, which is an Israeli state-owned defense manufacturer.

Mr. Kadish said he did not receive any payment from Mr. Yagur, beyond small gifts or dinner for Mr. Kadish and his family at a restaurant in the Riverdale section of the Bronx.

Mr. diGenova said he never came across Mr. Kadish’s name while investigating and prosecuting Pollard.

The allegations against Mr. Kadish cast doubt on Israel’s public claims that Pollard was the only American spying on this country on Israel’s behalf. The Israeli daily Haaretz reported yesterday on its Web site that in 2004, Israel secretly acknowledged to American authorities that Pollard was not the only spy.

Exactly why Mr. Kadish would speak to the FBI at this late date is unclear.

“At an advanced age, he may have thought, I’m not going to play games,” Mr. diGenova, who is now in private practice, said. “I’m going to tell him what I did and see where the chips fall.”

Mr. Kadish was arrested yesterday on charges of conspiring to disclose documents related to the national defense, which carries penalties up to a death sentence, as well as charges of conspiring to act as agent of Israel and of lying to a FBI agent.

A spokesman for Israel’s foreign ministry, Arye Mekel, said of the case against Mr. Kadish: “We were updated by the American authorities on the situation,” declining to comment any further.

After the first interview last month with FBI agents, Mr. Kadish received a phone call from Mr. Yagur, according to the complaint.

During that conversation Mr. Yagur gave instructions to Mr. Kadish about how to deal with the agents.

“Don’t say anything,” Mr. Yagur said in Hebrew, according to the complaint. “You didn’t do anything. What happened 25 years ago? You didn’t remember anything.”