Top congressional leaders have asked independent watchdogs to open an investigation into whether agencies deliberately gave them false information about a proposed $400 million-plus center for intelligence analysis overseas, according to a letter and documents reviewed by Fox News.

The April 27 letter was signed by House Permanent Select Committee on Intelligence Chairman Devin Nunes, R-Calif.; Armed Services Committee Chairman Mac Thornberry, R-Texas; Oversight Committee Chairman Jason Chaffetz, R-Utah; and Veterans Affairs Committee Chairman Jeff Miller, R-Fla.

They asked Acting Defense Department Inspector General Glenn A. Fine and intelligence community Inspector General I. Charles McCullough III to "initiate one or more inquiries into the allegations that inaccurate or misleading information was intentionally conveyed to Congress in connection to the selection of RAF Croughton, as the location for a Joint Intelligence Analysis Complex (JIAC)."

RAF Croughton is a base about 70 miles northwest of London that acts as a U.S. Air Force communications station. The Defense Department and intelligence community want to locate their proposed intelligence center for analysis at that base.

The central allegation – from lawmakers as well as documents citing whistle-blowers – is that government agencies gave Congress misleading information to support the selection of RAF Croughton, while downplaying other options that may have been more cost-efficient.

Nunes told Fox News that, considering military and intelligence-gathering funds have been cut, it makes no sense to build a new facility when other facilities are available across the NATO theater. He suggested the selection was fast-tracked.

"We've met with the deputy secretary of defense, we've met with the DNI director (James Clapper), and we've been very clear that they have not done a report, an analysis of alternatives that's real," Nunes said. "There's a lot of threats that are out all over the globe and no American thinks it's smart to build a new intelligence center right outside of London, which is one of the … most expensive areas in the world."

Nunes said when he and other congressional leaders began asking questions about why Croughton was the preferred location, government officials were not forthcoming.

"When Congress started asking questions, we didn't get straight answers and so myself and many others have asked the inspector general to come in and help us investigate because we believe that we've been misled," Nunes said. "When we finally figured out that they didn't look at multiple locations across the NATO theater, we knew at that point that there was something going on here that was turning into a fiasco."

The new intelligence center would be used by AFRICOM, which conducts intelligence analysis for the Africa Command as well as EUCOM -- which does the same for the European Command. There is no requirement for analysts to be located in the geographic area that they are assessing. For example, analysts who cover Iraq and Syria work at CENTCOM in Florida. And the AFRICOM headquarters is in Stuttgart, Germany.

The documents cited by lawmakers indicate "various whistleblowers have come forward alleging that the DOD has used faulty data in its analysis to achieve a preferred outcome, and has intentionally provided to Congress false information on housing and communication at Lajes Field,” which was a competing site. The whistleblower claims could not be independently verified.

According to the documents, Director of National Intelligence James Clapper told Nunes in July 2015 that senior "civilians and contractors" would "quit rather than move" to Lajes Field in the Azores, a group of mid-Atlantic islands.

The California lawmaker, whose family emigrated from the Azores, said he wants the most cost-efficient operation and disputes claims that he favored the Azores location because his family came from the islands years ago.

"A half a billion dollars -- that's real money. Look at what that could do for our military,” Nunes said. “Look at what that could do for intelligence. I think if you look at what's happened across Europe and Africa, our intelligence -- we're not getting enough."

A spokeswoman for the intelligence community inspector general, Andrea Williams, said their office received the letter and is deferring to the Defense Department inspector general -- and "if DoD IG needs our support and asks, we will provide it."

DOD IG spokeswoman Bridget Serchak said they have the request and it is under review. A source familiar with the discussions said Clapper had met with Nunes and raised various concerns about alternate sites.

A spokeswoman for the deputy secretary of Defense said RAF Croughton "remains the optimal location" for the intelligence center, and disputed allegations that the required selection process was not followed.

"The Department evaluated a number of alternative locations and of those 14 locations, Croughton rated the highest overall," Lt. Cmdr. Courtney Hillson said. "Lajes was not included as a candidate in the … analysis of alternatives because it did not meet the minimum operational requirements. For example, Lajes cannot cost-effectively provide the needed communications bandwidth. ... Lajes is not easily accessible, is not proximate to major transportation hubs, and its geographic remoteness does not provide the access we and all NATO members need.”

On allegations Congress was misled, Hillston said at least two separate assessments were conducted: "While we share the view of the importance of Lajes, the Department assesses that is not the best location for the [Joint Intelligence Analysis Complex]. The Department has participated in numerous briefings with the Congress about the location of the JIAC and well as the viability of Lajes, and we look forward to continuing to work together."