Mobley, 26, had mostly low-level jobs, hauling trash and other materials and constructing scaffolding for contractors at plants in New Jersey, Pennsylvania and Maryland from 2002 to 2008.

Mobley is a U.S. citizen, originally from Somalia, and has passed criminal background, drug testing, psychological and identity testing prior to getting work at the nuclear plants.

A Muslim who grew up in Buena, N.J., Mobley was among 11 al-Qaida suspects arrested earlier this month in Yemen. Officials there said that while on a hospital visit, Mobley snatched a gun and shot a security guard to death in an escape attempt from the hospital.

The Mobley case presents a thorny dilemma for security officials in the United States on where the quest for national security begins and the civil rights of the individual end.

With reports that Mobley had organized pilgrimages to the Middle East and attempted to convert high school classmates to Islam, some could rightfully question whether the background searches on him should have detected radical militant sentiments.

Our civil liberties are among our most prized possessions as U.S. citizens, but in a post-9/11 world, we might have to give up some of our freedoms in the name of national security, especially in light of the growth of radicalized American Muslims joining terrorist groups abroad.

The more I learn about Mobley, the more I am convinced he shouldn't have been allowed to go anywhere near a nuclear facility in the United States.