Three men are to appear in a US federal court today on charges of lying to federal agents about a plot to blow up unspecified targets in the United States, the Department of Justice said.
Najibullah Zazi (24) a native of Afghanistan who works as an airport shuttle bus driver, was questioned by the FBI for three days. He and his father, Mohammed Wali Zazi (53) were taken into custody on Saturday at an apartment in the Denver suburb of Aurora.
Also arrested was Ahmad Wais Afzali (37) a native of Afghanistan who was living in the Queens borough of New York City, a Department of Justice spokesman said.
Each faces a possible eight years in prison if convicted.
FBI agents say they found notes describing how to make bombs in the handwriting of the airport shuttle driver. Investigators also claims to have discovered his fingerprints on materials — batteries and a scale — that could be used to make explosives.
"The arrests ... are part of an ongoing and fast-paced investigation," David Kris, assistant attorney general for national security, said in a statement.
"It is important to note that we have no specific information regarding the timing, location or target of any planned attack," Mr Kris said.
According to affidavits filed in the case which document contacts between the three men and Najibullah Zazi's travels between Pakistan and the United States, FBI agents who searched Mr Zazi's rented car on September 11th found a laptop computer containing several pages of hand-written instructions on the manufacture of explosive devices.
"A physical scientist with the FBI laboratory has opined that the notes include the steps necessary to produce an effective explosive charge," said the court documents.
Each of the affidavits says "the FBI is investigating several individuals in the United States, Pakistan and elsewhere relating to a plot to detonate improvised explosive devices inside the United States".
One affidavit says Mr Zazi falsely told agents he had never seen the documents before or written them, but admitted that during a trip to Pakistan he had received instruction on weapons and explosives at an al Qaeda training facility.
Mr Afzali is accused of lying when he told agents in a written statement he had never warned Mr Zazi and his father authorities had sought information about them and that their phones were being monitored.
Mohammed Zazi was accused of falsely denying that he knew and had contacted Mr Afzali.
The arrests came after talks between Mr Zazi and federal authorities, which had stretched over three days, apparently broke down on Saturday and the suspect declined a fourth meeting, choosing to consult with his lawyers instead.
In a telephone interview with the Denver Post newspaper on Saturday morning, Mr Zazi said that contrary to media reports he had not admitted to any link to al Qaeda or participating in training with the group in Pakistan.
"It's not true," Mr Zazi told the newspaper. "I have nothing to hide. It's all media publications reporting whatever they want. They have been reporting all this nonsense."
FBI Director Robert Mueller has reassured lawmakers in Washington that there is no imminent security threat related to the investigation surrounding Mr Zazi, but has declined to elaborate publicly on the probe.
FBI agents entered Mr Zazi's residence on Wednesday afternoon with a search warrant and the entire three-story apartment building was roped off with yellow crime-scene tape.
Authorities put black screens over the building's windows to prevent onlookers from seeing inside, and a house a few miles away was likewise cordoned off.
The questioning of Mr Zazi came days after he travelled to New York City. He was stopped by authorities on September 10th while driving a rental car on the George Washington Bridge, which connects New York City with New Jersey, but later returned to Colorado by airplane, his lawyer said.
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