WASHINGTON -- FBI agents who ensnared a suburban father in a terrorism sting involving a fictional subway bomb plot have turned their attention to figuring out what made the Pakistani-born U.S. citizen turn against his adopted country, officials said.

Law enforcement officials said they believe Farooque Ahmed was radicalized in the United States, becoming the latest in a string of U.S. citizens charged with plotting terrorist attacks against here.

FBI agents were tipped off to Ahmed in January, when a source inside the Muslim community said the 34-year-old telecommunications worker was asking around, trying to join a terrorist group and kill Americans overseas, the officials said, speaking on condition of anonymity because the investigation continues.

Since the Sept. 11, 2001 terrorist attacks, the FBI has tried hard to build relationships inside the Muslim community. The White House has made combatting homegrown terrorism part of its national security strategy.

Born in Lahore, Pakistan, Ahmed arrived in the U.S. in 1993 and became a citizen in 2005, officials said. He worshipped at the All Dulles Area Muslim Society, which is known for its mainstream Islamic congregation. Ahmed has not been back to Pakistan since 2005 and has no ties to terrorist groups there, officials said.

Like many would-be terrorists and sympathizers, Ahmed was potentially influenced by Anwar al-Awlaki, the radical Muslim cleric who preached in northern Virginia until 2002 and now lives in hiding in Yemen, officials said. But while Ahmed listened to al-Awlaki's Internet sermons, officials said the two were not in contact and they're not sure how influential those sermons were.

In April, Ahmed thought he had found what he wanted: a pair of Al Qaeda operatives who would help him carry out a bomb attack on America's second-busiest subway system, according to court documents unsealed Thursday. But the operatives were really undercover investigators, the officials said. And the meetings at local hotels were all staged with the FBI's cameras rolling.

What followed was an elaborate ruse in which Ahmed was given intelligence-gathering duties and coded information in a Quran as part of the supposed plot to kill commuters.

The FBI searched Ahmed's house on Wednesday, pulling out guns and ammunition, officials said. He was scheduled to be in court Friday for a hearing on whether he can be released while awaiting trial. Prosecutors are expected to argue he is too dangerous.

Farooque Ahmed was a married father with a good job with a telecommunications company. He was also, authorities say, eager to fight Americans in Afghanistan and committed to becoming a martyr.

Ahmed was arrested Wednesday, just weeks before, the FBI says, he planned to make the annual religious pilgrimage to the Islamic holy city of Mecca in Saudi Arabia.

Ahmed faces charges of attempting to provide material support to a designated foreign terrorist organization, collecting information to assist in planning a terrorist attack on a transit facility, and attempting to provide material support to terrorists.

Prosecutors say he videotaped four northern Virginia subway stations, suggested using rolling suitcases instead of backpacks to pack the explosives and said he wanted to donate $10,000 to help the overseas fight.