Faisal Shahzad, the Pakistani-American suspect in the Times Square bombing attempt, has been linked to Tehrik-i-Taliban Pakistan (TTP) and a Yemeni-American militant cleric who has inspired several recent attacks and plots.
The extent of Shahzad's involvement with TTP has not been determined and could range from communications to training and does not necessarily mean that TTP directed the attack, CNN reported Thursday citing law enforcement and US intelligence officials.
CNN cited another official as saying 30-year-old Pakistani-American connections to TTP were "plausible," but noted that numerous connections among insurgent groups in Pakistan made it difficult to zero in on a single responsible group.
New leads developed from the Pakistani end of the investigation show Shahzad likely had training in Pakistan from extremists, CNN said citing another official who would not say if the training was specific to the Times Square bombing attempt. Investigators had not concluded from which group Shahzad may have received help, the news channel said citing yet another official.
But the New York Times said investigators believe he was trained by the Pakistani Taliban which previously focused mainly on Pakistani government targets. The influential daily cited a senior military official as saying Shahzad had told interrogators that he met with Pakistani Taliban operatives in North Waziristan in December and January. Later he received explosives training from the same operatives.
The Times also cited an official as saying Shahzad has told investigators that he was "inspired by" the violent rhetoric of Yemeni-American cleric Anwar al-Awlaki Awlaki.
To counterterrorism officials it is no surprise to find that a terrorist suspect had been influenced by Awlaki, 39, now hiding in Yemen, who has emerged as perhaps the most prominent English-speaking advocate of violent jihad against the United States, the Times said.
Earlier this year, the Obama administration took the extraordinary step of authorising the killing of Awlaki, making him the first American citizen on the Central Intelligence Agency's hit list, the daily noted.
In two recent US cases, Awlaki communicated directly with the person accused in the attack, the Times noted.
Nidal Malik Hasan, the US Army psychiatrist accused of killing 13 people at Fort Hood, Texas, in November, exchanged about 18 e-mail messages with Awlaki in the year before the shootings.
Umar Farouk Abdulmutallab, the Nigerian man accused of trying to blow up a trans-Atlantic airliner on Christmas Day, is also believed to have met Awlaki during his training by Al Qaeda in the Arabian Peninsula.
But it is unclear whether Shahzad ever directly communicated with Awlaki, the Times said.
Multiple media reports said a day before the failed attack, Shahzad carried out a dry run, parking his Isuzu SUV on West 38th Street between 9th and 10th avenues a few blocks from Times Square to be used the following day as a getaway car.
But on Saturday, after he left the smoking Pathfinder on West 45th Street just west of Broadway and walked to the Isuzu, he realised he didn't have the Isuzu keys, the reports citing unnamed sources said. So he headed to Grand Central Terminal and boarded a train to Connecticut.
The Wall Street Journal said while investigators have so far found no evidence of any US accomplices - indeed, the fact that he parked his own getaway car suggests he was acting alone - they continue to chase leads in the case.