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 where he might avoid prosecution.
He received the training in the federally administered tribal areas of Pakistan, the documents say.
The FBI said it found images of nine pages of handwritten notes on a laptop containing formulas and instructions for making bomb, 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 Sept. 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.
Crews of journalists clustered outside Afzali's home in Queens.
No one answered the doorbell at the three-story brick residence, adorned with brightly colored flower boxes.
Ron Kuby, Afzali's attorney, told WNYW-TV in New York on Sunday that law enforcement officials initially came to his client requesting his help in the investigation.
"He was doing exactly what the government says they want people to do: cooperate," Kuby said. "He didn't go to the FBI. The FBI came to him. They asked him to do things. He did those things. And as a result of his cooperation, he ends up being charged, not with some act of terrorism, but with allegedly lying to the FBI."
Carl Tobias, a law professor at the University of Richmond who has been tracking terrorist investigations around the country, said authorities could have made the arrests now because they feared too much information was getting out to the suspects. Additional charges could be filed later, he said.
FBI agents say Najibullah Zazi traveled to Pakistan twice this year on Jan. 15 and most recently on Aug. 28. Zazi says he was visiting his wife, who lives in the Peshawar region.
The investigation escalated after Zazi rented a car and drove from Denver to New York, crossing into Manhattan on Sept. 10. Zazi said he went to New York to resolve some issues with a coffee cart he owns in Manhattan, then flew home to Denver. The FBI searched Zazi's rental car and laptop during the New York trip and listened in on telephone conversations, according to the affidavits.
On Monday, FBI agents and police officers with search warrants seeking bomb materials searched three apartments and questioned residents in the Queens neighborhood where Zazi stayed.
An arrest warrant affidavit says FBI agents intercepted a phone conversation around Sept. 11 in which Afzali, a legal permanent resident from Afghanistan, told Zazi that he had spoken with authorities. "I was exposed to something yesterday from the authorities. And they came to ask me about your characters (sic).
They asked me about you guys," Afzali told Zazi, according to the affidavit.
However, Afzali allegedly lied to authorities about that conversation when federal agents asked him about it Thursday, according to the affidavit.
The department says Mohammed Zazi, a naturalized U.S. citizen who was interviewed last week by the FBI, lied when asked if he knew anyone by the name of Afzali and said he didn't. The FBI said it had wiretapped a conversation between Mohammed Zazi and Afzali during Najibullah Zazi's visit to New York.
The FBI also searched Zazi's apartment and his uncle and aunt's home last week in suburban Denver. Authorities have not said what they found.
Zazi was born in Afghanistan in 1985, moved to Pakistan at age 7 and emigrated to the United States in 1999. He returned to Pakistan in 2007 and 2008 to visit his wife, according to Folsom.
At the mosque in Queens where Zazi recently visited, Masjid Hazrat Abu Bakr, worshippers marked the end of Ramadan on Sunday.
Zakir Khan said he had seen Zazi praying at the mosque recently, after not seeing him there for about a year. Zazi told him he was back in the city to get his coffee truck, to take it back to Colorado. Zazi spoke to Khan about his hopes of one day opening a limo business.
The New York Daily News reported Saturday that investigators spent several hours earlier this week at a U-Haul in Queens, where some men under scrutiny in the case tried to rent a large truck.
A manager at the rental lot, Robert Larson, told the newspaper the men went away empty handed because they didn't have a valid credit card. The paper reported that U-Haul workers identified one of the people involved in the rental attempt as Naiz Khan, an Afghan immigrant in Queens who knew Zazi and has been questioned by the FBI in connection with the case.
"I've never been to that U-Haul," he said Saturday. Asked what he thought about the scrutiny of Zazi, Khan said he wasn't sure. "My opinion is, I don't know him. I know him from a mosque, that's all. He's my friend."
QUICK HEADLINES | NEW YORK NEWS | GET NEWSLETTERS
-----------------------------------------------------------------------------------------------
ABC 7 SOCIAL NETWORKING
Find us on Facebook® | Follow us on Twitter
More social networking
-----------------------------------------------------------------------------------------------
MORE FROM ABC 7
ABC 7 widget | Most popular stories |
Street-level weather
Mobile Alerts |
Report Typos |
See News? Tell Eyewitness news
-----------------------------------------------------------------------------------------------
