Federal investigators say they believe that money used to finance the bombing of the World Trade Center was transferred in recent months from Europe to a New Jersey bank account used by the two suspects now under arrest.

One law-enforcement official said the FBI was trying on Wednesday night to trace the source of the wire transfer and that the existence of the money trail "suggests some foreign group was financing them."He said the money did not appear to have come from either man's family or homeland, but from other possible sources that he declined to name.

Other officials said at least $8,000 had been transferred by wire from Europe in recent months into the joint account, which was listed in the names of Mohammed A. Salameh, Nidal A. Ayyad and others who were not identified.

The officials said that money from the account, at a National Westminster Bank branch situated near a fundamentalist mosque in Jersey City, was withdrawn some time later by Salameh. He is suspected of leasing a storage locker where bomb-making chemicals were mixed and renting the van that carried the bomb into a trade center parking garage.

One senior investigator said that identifying the foreign source of the money was expected to help explain a motive behind the Feb. 26 attack, which killed at least five people, injured more than 1,000 and crippled the city's tallest office complex.

The existence of the joint account, mentioned Wednesday in the federal criminal complaint against Ayyad, and a disclosure from investigators that they were also examining three other bank accounts held by other people who have not yet been charged, added a new dimension to the case.

It also fed a growing perception by investigators that despite achieving its goal, the plot to bomb the trade center was extremely inept in many ways.

"I wish I knew if I had amateurs, wannabe terrorists, or terrorists here," said one senior law-enforcement official who spoke on the condition of anonymity and who, like many of his associates, professed amazement at the evident gaffes committed by the suspects.

Ayyad, a 25-year-old Rutgers College microbiology and chemistry graduate who lived in Maplewood, N.J., and worked at the Allied-Signal chemical corporation in Morristown, was arrested Wednesday. Not only, the government contended, were he and Salameh listed as joint holders of the bank account, they also leased a car together on Feb. 15: a red Oldsmobile Ciera.

In addition, the federal complaint said, Salameh called Ayyad at his office four times on Feb. 25, the day before the bombing, from a pay telephone at the storage center where the chemicals were found, and had Ayyad's business card on him when he was arrested.

The complaint suggested that Ayyad accompanied Salameh to a Ryder truck rental office in Jersey City Feb. 23, when Salameh used his own name to lease the Ford rental van that was later traced through a fragment of the wreckage and identified as the vehicle with the bomb.