An undercover investigator with a fake bomb hidden on his body last week passed through a metal detector, went through a pat-down at New Jersey's Newark Liberty Airport, and was never caught, the Transportation Security Administration said today.

"It's sort of like a red teaming scenario," said Frank Cilluffo of the Homeland Security Policy Institute. "You intentionally look for where the weak point is in the system. I think it clearly identified a vulnerability."

The TSA said today that its "red team" tests occur weekly all over the U.S. and that the agency refused to say how many times its officers had failed to find the hidden device.

The agency said that the device was not intended to be detected. The agent does not go through other layers of security such as scanners.

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"We do this all the time," a TSA official said. "And all the time, we have successes and failures."

New York Rep. Peter King, however, requested a "top-to-bottom" review today of TSA operations at Newark, according to The Associated Press.

The focus on devices and liquid explosives is the big reason why the TSA says it will stop looking for pocket knives and allow them onto aircraft.

But that plan is facing increasing backlash. Flight attendants, using the White House petition site, already have 10,000 signatures demanding the policy banning pocket knives remain.

And air marshals and some pilots are now joining the effort, saying they will ask Congress to intervene and halt the planned change.

The head of the TSA said he was standing by his decision.