Not long ago, the notion of homegrown youth abetting foreign terrorists targeting Americans would have been unthinkable.
The parents of American-born Taliban soldier John Walker Lindh supported their son's decision to go to Yemen, and later Pakistan, to memorize the Quran and become an Islamic scholar. After his arrest, Lindh's father insisted his son was not involved in a fight against the United States but in a war among Afghans when the Muslim convert joined the Taliban army to fight the Northern Alliance.
The younger Lindh was charged with conspiring to kill Americans and supporting terrorists but pleaded guilty in 2002 to lesser offenses, including carrying explosives for the Taliban. He is scheduled to be released from prison in 2019.
In the case of the young men in Pakistan, authorities are trying to determine whether the father of one of the young men played a role in their plans.
Pakistani police said Khalid Farooq, the father of Umer Farooq, had been taken into custody. The father had a computer service and repair business in Virginia and shuttled between the United States and Pakistan.
Umer Farooq's mother, Subira, told CNN that her son would never plot a terror attack.
In another recent case, the father of Denver-area terror suspect Najibullah Zazi has himself been charged with lying to the FBI when authorities asked him about his son.
Mohammed Zazi told the Denver Post there had been a mistake when it was reported that his son was involved in a terror plot.
"Everyone has made a mistake. The media has made a mistake," he insisted.
Since the Sept. 11, 2001, terror attacks, investigators have tried to cultivate American Muslim sources who could help identify potential security threats. Government officials visit mosques, attend national Muslim conventions and very publicly celebrate Muslim holidays. In the latest case, family members contacted the Council on American-Islamic Relations, or CAIR, with concerns about their children before they were arrested. And the council put them in touch with the FBI and got them a lawyer.
National American Muslim groups and religious leaders in individual communities, have encouraged community members to cooperate with law enforcement and monitor their communities.