FBI Searches Home of Colo. Terror Suspect

Updated at 6:36 p.m. EDT

FBI agents are searching the home of a Colorado man identified by law enforcement as having a possible al Qaeda link.

FBI agents and sheriff's deputies entered the home of Najibullah Zazi in suburban Denver on Wednesday. FBI special agent Kathleen Wright confirms they are executing a search warrant.

Zazi is at the center of what law enforcement sources say may be one of the most important U.S. terrorism investigations since 9/11, reports CBS News correspondent Bob Orr.

Zazi said he is worried about his future after learning that he was under law enforcement surveillance for the alleged al Qaeda links. The 25-year-old Afghan national once had a hot dog cart in New York and now drives an airport shuttle van in Denver. He denied that he's a central figure in a terrorism investigation that fed fears of a possible bomb plot and led to several police raids in New York City.

"I am an airport driver and that's all I can say," Zazi, 24, said Tuesday at his suburban Denver home, which boasts a panoramic view of the Rocky Mountains. "This could look bad on me. It could damage my business."

Two law enforcement officials told The Associated Press that a joint FBI-New York Police Department task force had put Zazi under surveillance because of the suspected links.

The task force also feared Zazi may be involved in a potential plot involving homemade hydrogen peroxide-based explosives like those cited in an intelligence warning issued Monday, said the officials, who spoke on anonymity because they were not authorized to speak about the investigation.

After Zazi traveled to New York City over the weekend, FBI agents and police officers armed with search warrants seeking bomb materials staged a surprise raid that rattled an urban, predominantly Asian neighborhood in Queens. Investigators searched three apartments and questioned residents, including Naiz Khan, who grew up with Zazi in New York City.

"Clearly they were real bad guys, and they were up to no good," a source told CBS News investigative producer Pat Milton.

Khan, an Afghan immigrant, said the FBI questioned him for about two hours about Zazi, whom he said stayed at his apartment last week.

"I can't tell. I don't know" about a connection between Zazi and terrorism, Khan said. "If there is, I'm not sure."

The FBI confiscated between 5 and 10 backpacks, computers, cell phones and other material during the raid in New York, CBS News reports. Investigators are combing through the items trying to identify other members of a potential network, e-mails of overseas contacts, bank statements and if Zazi was being directed by senior Al Qaeda leadership.

U.S. officials, speaking on condition of anonymity, say Zazi also recently traveled to Pakistan, made contact with known al Qaeda operatives, and sought information about building home-made hydrogen peroxide bombs, Orr reports.

"There was enough here that gave a sick feeling in your stomach. You can only see so much looking through the peep hole," a source told CBS News.

No arrests were announced, and the FBI and NYPD have refused to discuss the case, leaving unanswered questions about the nature, scope and intent of the potential plot.

A senior law enforcement official says New York police and the FBI lacking hard intelligence and fearing a possible attack were forced "to move early as a security precaution," Orr reports. Now, those disruptive raids have "badly compromised" FBI surveillance in the case, the official said.

CBS News has also confirmed that literature on bomb making was found in Zazi's possession.

The FBI still lacks evidence of any hard plot, Orr reports. Figuring the case, one intelligence official said, is like untangling a plate of spaghetti.

Colorado elected officials who had been briefed on the probe said there was no imminent threat.

Monday's FBI and Homeland Security intelligence warning, issued to police departments nationwide, listed clues that could tip off police to peroxide-based bombs, such as people with burn marks on their hands, faces or arms; foul odors coming from a room or building; and large industrial fans or multiple window fans.

The warning, obtained by the AP, also said that the homemade explosive materials can be hidden in backpacks, suitcases or plastic containers.

Zazi's attorney, Arthur Folsom, said Zazi contacted him immediately after hearing from his friends in New York that their homes had been raided.

"Given some of the course that has happened in this country in recent years, he was more worried that he would be swooped into the back of a van and that he wouldn't be able to speak to a lawyer or family," Folsom said. "I told him our government doesn't have that policy any more."

Folsom said he planned to host a Wednesday news conference in Denver.

The lawyer also said Zazi drove to New York in a rented car to take care of a problem with the location of a coffee cart that he co-owns with a friend, and to visit friends.

Zazi said he was among several drivers stopped by police on Sept. 10 on the George Washington Bridge, which connects New Jersey to Manhattan, and that officers told the drivers they were conducting random searches for drugs. Zazi said he consented to a search of his vehicle and was allowed to leave.

In New York, Folsom said, Zazi's car was towed because of a parking violation. Police searched both the car and a laptop inside, Folsom said.

"They found nothing, didn't ask him any more questions and sent him on his way," Folsom said. "If they had had found anything, he would be in the company of the federal officials in New York."

Zazi returned the car to an airport and flew home to Denver, Folsom added.

Zazi's 35-year-old aunt, Rabia Zazi, said from her suburban Aurora home that her nephew recently visited the Peshawar region of Pakistan - where she said his wife lives and whom he hopes to bring to the United States.

She said Zazi was born in Pakistan but moved to the United States at an early age and grew up in Queens. He moved to Colorado several months ago to help his father with his shuttle business, she said.

She said her nephew often travels to Pakistan to spend time with his wife. Folsom said Zazi spends three months of the year in Pakistan.

But a review of government travel databases shows that Zazi only entered the United States once, in 2004, reports CBS News investigative producer Len Tepper. It's possible that Zazi traveled under another name, didn't enter the U.S. directly, or that the government database didn't record his flight.