Claims that an Afghan immigrant was on the verge of unleashing a terrorist attack on New York City on the anniversary of the Sept. 11 attacks are missing a key element: explosives or the chemicals allegedly used to make them, the man's attorney said.

FBI agents have yet to find those elements and connect them to Najibullah Zazi, charged with conspiring to use weapons of mass destruction in a plot authorities say was aimed at commuter trains, attorney Arthur Folsom told a federal judge in Denver Friday.

U.S. Magistrate Judge Craig Shaffer ultimately ordered Zazi's transfer to New York, and Zazi was taken there by federal marshals.

"No traces of any kind of chemical was found in his vehicle," Folsom said of an FBI search of Zazi's car.

A federal prosecutor argued that Zazi was planning an attack to coincide with the 9/11 anniversary.

"The evidence suggests a chilling, disturbing sequence of events showing the defendant was intent on making a bomb and being in New York on 9/11, for purposes of perhaps using such items," prosecutor Tim Neff told Shaffer.

Zazi was stopped by police on Sept. 10 as he entered New York, and he dropped his plans for an attack once he realized that law enforcement was on to him, prosecutors allege.

Prosecutors said Zazi received explosives training from al-Qaida in Pakistan and returned to the U.S. bent on building a bomb.

Over the summer, he and three associates went from one beauty-supply store to another in a Denver suburb buying chemicals to make explosives like those that killed dozens of people in transit bombings in London and Madrid, investigators said.

At least three and possibly more of his accomplices remain at large, and investigators have fanned out across New York in pursuit of suspects. Authorities also issued a flurry of terrorism warnings for sports complexes, hotels and transit systems.

A law enforcement official who spoke on condition of anonymity because of the ongoing investigation said associates of Zazi visited Colorado to help him buy the chemicals using stolen credit cards before returning to New York.

Another law enforcement official said that authorities had been especially worried about Zazi's Sept. 10 visit to the city because it coincided with a visit by President Barack Obama. Police considered arresting him right away. The official spoke on condition of anonymity because the investigation continues.

Police have been especially active in the neighborhood in Queens where Zazi visited during his New York trip, staying at an apartment with a group of cab drivers and food cart operators he knows.

Folsom said prosecutors lack direct evidence that Zazi was involved in bomb-making, finding none of those materials in Zazi's car, his Aurora, Colo., apartment or apartments Zazi visited in New York. FBI agents said they found Zazi's fingerprints on a scale and batteries during a search in Queens, but Folsom said those items have no connection to the alleged plot.

"I think they were hoping that people would just jump to conclusions," Folsom said in an interview with The Associated Press.

Zazi ran a coffee cart in Manhattan before moving to Denver this year and getting a job as an airport shuttle driver.

FBI raids beginning Sept. 14 rattled a quiet, predominantly Asian neighborhood in Queens. Muslim men said dozens of FBI agents ransacked their homes and questioned them for hours, sometimes taking DNA samples and prints from their shoes.

The FBI has also been visiting beauty shops and home-improvement stores in Colorado and New York for details about the alleged bomb-making purchases.

Court papers say that during the summer, Zazi and three unidentified associates bought "unusually large quantities" of hydrogen peroxide and acetone -- a flammable solvent found in nail-polish remover -- from Denver-area beauty supply stores. The products had names such as Ion Sensitive Scalp Developer and Ms. K Liquid 40 Volume.