Testifying at the federal obstruction-of-justice trial of Zazi's father, the cousin told jurors that he had introduced Zazi to a cleric in Pakistan who arranged for Zazi and two childhood friends from Queens to get training at an al-Qaida outpost.
"There are three guys who want to go to Waziristan," cousin Amanullah Zazi, who was living in Pakistan at the time, recalled telling the cleric.
Najibullah Zazi has pleaded guilty, admitting that he returned from Pakistan to his family's home in Colorado to cook up homemade bombs. He then drove to New York City in September 2009 with plans to attack the subway system in a "martyrdom operation" that was foiled by the FBI.
Amanullah Zazi pleaded guilty in secret and agreed to become a government witness in federal court in Brooklyn against Najibullah Zazi's father, who was charged in an alleged cover-up.
The father, Mohammed Wali Zazi, "tried to cover Najibullah Zazi's tracks by concealing facts and destroying evidence," Assistant U.S. Attorney Andrew Goldsmith said Monday in opening statements.
The elder Zazi has denied knowing anything about a plot that left New Yorkers severely shaken but unharmed.
"He was confused and in the dark," defense attorney Justine Harris said in her opening statement.
As one of the first witnesses, the 24-year-old cousin described how the FBI and immigration agents put the squeeze on the Zazi clan as the plot was unraveling.
When it became clear Najibullah Zazi was a suspect and family members were getting grand jury subpoenas, the cousin said "Uncle Wali" recruited him to get rid of plastic container of peroxide and other chemicals used for bomb-making and other evidence that was stashed in Colorado. The family agreed to code name the chemicals "medicine" in case the FBI was eavesdropping, he said.
He also claimed his uncle urged him to lie to the grand jury. The family agreed, he said, "If anybody asks questions, tell them we don't know nothing."
Amanullah Zazi testified that he decided to plead guilty in January 2010 and cooperate in hopes of avoiding a maximum 30-year sentence.
The cousin appeared in court wearing a blue inmate uniform. Speaking in a lifeless monotone, he explained he had been jailed about a week ago after telling government officials that he wasn't sure he wanted to testify and had been using marijuana and cocaine.
A brother-in-law of the defendant also has pleaded guilty and is expected to testify.
Najibullah Zazi and one of the two friends charged as would-be suicide bombers are awaiting sentencing. The third man has pleaded not guilty and could go to trial later this year.