Obama Administration officials set a realistic tone as they urged Iran to return the CIA drone in their possession.
“With respect to the drone inside of Iran, I’m not going to comment on intelligence matters that are classified, “ President Obama told reporters during a joint news conference with the Iraqi Prime Minister Nouri al Maliki. “As indicated, we have asked for it back. We’ll see how the Iranians respond.”
Secretary of State Hillary Clinton also set low expectations during a news conference with Britain Foreign Secretary William Hague. “With respect to actions regarding Iran, we are making known our concerns. We submitted a formal request for our lost equipment as we would any government, but we do not expect them to comply.”
While intelligence officials are investigating a handful of scenarios to explain the lost CIA drone now held in Iran, Fox News has learned that a leading scenario is that the drone went into a default setting for an automatic landing pattern.
But the pressing question remains what triggered it.
"The forensics are ongoing," said an official.
One U.S. official said the landing was in line with an "internal or system failure" that would be consistent with the "default setting" theory.
Two intelligence sources, who work cyber issues, say the other scenarios include a catastrophic or navigational malfunction that caused the RQ170 to break contact with its base. But that scenario is problematic, the sources said, because it does not fully explain the "soft landing, one where it lands and lands well, not scratched up."
Once contact with the operators is broken, drones such as the RQ170 are programmed to circle an area until contact is re-established, sources said. If contact is not re-established during a pre-programmed period, it is designed to return to base or to self-destruct -- directed through a separate channel or program. A common outcome is that the drone crashes and is burned by its fuel.
Most concerning to investigators is that none of these steps occurred.
Under a third scenario, which is described as "plausible, but remote," the drone's data stream was compromised or jammed. One U.S. official emphasized that there was "no evidence of jamming" or that "hostile fire took down the drone."
Former UN ambassador, John Bolton, speculated this weekend that Tehran maybe getting help from Moscow. “If the Russians have provided Iran with sophisticated jamming equipment it means a lot else is at risk too -- missiles, planes, and communications and guidance systems for a whole range of our weapon systems.”
While Iran has not shown the ability to break encrypted code of the sophistication that would be needed to reorient a drone, the Russians and Chinese are more advanced -- and have incentive to help Iran. The drone and other unmanned aerial vehicles are "flown by wire," meaning the flight controls are operated electronically.
How far the Russians and Chinese have "got into the code is one of the big unknowns," one intelligence source said.
The link between operators and the drone was breached on Nov. 29, and it was not immediately known to the U.S. military or CIA if the drone had crashed. The lengthy search led some to believe they "were looking for a drone in many pieces."
Asked about the drone, President Obama said Monday he would not comment "on intelligence matters that are classified."
"As has already been indicated, we have asked for it back, we'll see how Iranians respond," Obama said.
U.S. officials are reluctant to describe the capabilities of the drone. It is understood that it can be used for video mapping of targets on the ground including buildings and tunnels as well as drawing samples or emissions. This would be important for surveillance over Iran.
As for Iranian claims it was decoding the drone, U.S. officials acknowledge concern the drone is down, but say "it is not a guaranteed gold mine for Iran, in part, because it is not clear they have the expertise to capitalize."
Both the CIA and Defense Department declined to comment citing the sensitivity of the program.
The Associated Press contributed to this report.
Catherine Herridge is an award-winning Chief Intelligence correspondent for FOX News Channel (FNC) based in Washington, D.C. She covers intelligence, the Justice Department and the Department of Homeland Security. Herridge joined FNC in 1996 as a London-based correspondent.