DENVER: Investigators said they found notes describing how to make bombs in the handwriting of an airport shuttle driver arrested as part of a terrorism investigation, and they also discovered his fingerprints on materials -- batteries and a scale -- that could be used to make explosives.

Najibullah Zazi arrives at the offices of the FBI in Denver for questioning on in this September 17, 2009 file photo. [Agencies]

The emerging details show that Najibullah Zazi, who has admitted receiving weapons training from al-Qaida, played a direct role in an alleged terror plot, authorities said in court documents released Sunday.

Zazi, 24, has publicly denied being involved in a terror plot. Zazi, his father, and an imam in New York City were arrested late Saturday on charges of making a false statement to the government, though legal experts say more charges could be coming.

Zazi's defense team denied reports that Zazi considered a plea deal related to terror charges, and Zazi's attorney, Arthur Folsom, dismissed as "rumor" any notion that Zazi played a crucial role. Zazi's defense team did not respond to repeated attempts to reach them Sunday.

Federal officials in Denver declined to comment.

Zazi admitted to FBI agents that he received instructions from al-Qaida operatives on subjects such as weapons and explosives. Court documents filed in Denver say Zazi was speaking with agents under an agreement through which he might avoid prosecution.

The FBI said it found images of nine pages of handwritten notes on a laptop containing formulas and instructions for making bombs, detonators and a fuse.

Zazi told the FBI that he must have unintentionally downloaded the notes as part of a religious book he downloaded in August. Zazi said he "immediately deleted the religious book within days of downloading it after realizing that its contents discussed jihad."

However, an arrest affidavit says the handwriting on the notes appeared to be Zazi's. The affidavit doesn't mention that they were part of a book, but that they were e-mailed as an attachment between accounts believed owned by Zazi in December, including an account that originated in Pakistan.

"It appeared to be consistent with the handwriting as it appeared in the document," an FBI agent wrote of comparisons of Zazi's handwriting with the notes.

In addition, agents found Zazi's fingerprints on a scale and double-A batteries seized during a raid at a home in the New York City borough of Queens on September 14.

Zazi, who lives in the Denver suburb of Aurora, underwent three days of questioning by the FBI before his arrest.

Also arrested were his father, Mohammed Wali Zazi, 53, in Denver; and an associate, Ahmad Wais Afzali, 37, of New York City, the Justice Department said Sunday. Both also were charged with making false statements to federal agents, which carries a penalty of eight years in prison.

Court appearances for all three were set for Monday.

Both Mohammed Zazi and Afzali face charges for allegedly lying to FBI agents about calls between Denver and New York. While prosecutors are seeking to detain Najibullah Zazi, prosecutors say they're not seeking detention for Mohammed Zazi, his father.

It was unclear from court documents whether officials would seek to detain Afzali, an imam at a mosque in Queens who has worked as an informant for New York police.