Investigators check Zazi's calls

WASHINGTON — An Afghan immigrant accused of plotting a terror attack in New York City contacted associates there while making a cross-country drive from Denver, raising concerns among investigators that he was sending instructions to purchase more bomb-making chemicals, officials familiar with the case said.

Terrorism investigators are trying to determine whether suspect Najibullah Zazi sent instructions to associates as he drove from Denver to New York last month, according to law enforcement officials. Such instructions could explain a critical missing piece of the high-profile terrorism case: why authorities could not find actual explosives.

Two officials, who spoke on condition of anonymity because they were not authorized to discuss the case, told the Associated Press that as Zazi drove, he was in communication with associates, and one of the officials said investigators believe the communications included instructions for the associates to purchase more chemicals for homemade bombs.

The officials did not describe the nature of the communication, but court documents indicate investigators have been examining Zazi's cell phone and e-mail traffic.

Asked Thursday about the Zazi communications, New York Police Commissioner Raymond Kelly declined to comment.

Court documents indicate that the 24-year-old Zazi and others were hitting beauty supply stores, buying concentrated bottles of hydrogen peroxide. He and others also bought acetone — nail polish remover — and other ingredients that can be used to make a powerful and highly unstable explosive. The same explosive was used by would-be shoe bomber Richard Reid in 2001 and the terrorists who carried out the London bombings in 2005 that killed 52 people.