Updated

Plans by the administration to use U.S. criminal courts to prosecute those responsible for last year’s terror attack in Benghazi have thrown up yet another roadblock to investigating the case, the Republican chairman of the House Intelligence Committee told Fox News Friday.

"This whole plan has been, all along, to bring them to a criminal court in the United States. I'm not sure that's in our national security best interest," Congressman Mike Rogers of Michigan said in an exclusive interview. "I don't know how anyone could come to the conclusion that it hasn't slowed it down."

"Certainly I'm frustrated, I think the committee's frustrated, and by the way, I think the people who do this for a living are really frustrated," Rogers said.

Based on intelligence reporting, the delay has allowed the Benghazi suspects to remain free and engaged within their terrorist organizations.

As for possibly targeting them with drone strikes, counter terrorism analysts say the administration's prosecution strategy has effectively pushed that option aside.

"U.S. intelligence officials, and our war fighters in the Defense Department, are hamstrung by a law enforcement model," said Thomas Joscelyn of the Center for Defense of Demcracies.

"There are a lot of guys who are known terrorists, who are known suspects in the Benghazi attack, who could be taken off the battlefield today."

The military detention center at Guantanamo Bay is also off the table for holding and questioning the Benghazi suspects

"Our position on GTMO is certainly clear, that we are not sending anyone to GTMO, that in fact, we are working to reduce the population at GTMO, ultimately with the goal of closing it." Marie Harf. State Department spokeswoman, said Friday.

Another problem is that while a criminal case requires physical evidence, by the time the FBI reached the consulate where four Americans died on Sep. 11, 2012, the crime scene was contaminated.

While the Libyan government has said it wants to help, then-outgoing FBI Director Robert Mueller told Fox News last month the situation there was too unstable to offer the U.S. the support it needs for a complex international case.

"It's hard to know who to deal with, you do not have the security forces that we've developed a rapport with, or the capabilities that we would hope," Mueller said in an August 22 interview.

“Benghazi and Derna (eastern Libya) are basically uncontrolled areas of Libya, where persons who are seen to be in some way affiliated with the central government are assassinated,” he said.

“Consequently, it is a difficult environment to do the investigation. But that being said, I can tell you that we have pressed, pressed ahead."

Fox News received no immediate response when it asked the Justice Department why it was so committed to pursuing a criminal prosecution in the Benghazi case, given the allegations that was slowing down the investigation