EXCLUSIVE: The director of the Federal Air Marshal Service is retiring after being investigated for his role in an alleged operation to acquire guns for officials' personal use, FoxNews.com has learned.

Director Robert Bray's home was raided in December in connection with the ongoing probe, according to sources and documents. Law enforcement and congressional sources told FoxNews.com that Bray's recently announced retirement, which is effective in June, is directly related to the investigation.

Transportation Security Administration officials say no such raid ever happened.

But Bray allegedly is among several officials who were obtaining weapons through this operation.

The probe stems from whistleblower accusations involving federal Air Marshal supervisor Danny Poulos. Sources say the Department of Homeland Security inspector general is involved, and possibly the Bureau of Alcohol, Tobacco, Firearms and Explosives. TSA officials disputed that those agencies are involved, but acknowledged that there is an internal review underway by the TSA Office of Inspection into the supervisor's alleged activity.

The supervisor, a TSA official confirmed to FoxNews.com, is "on administrative leave."

Poulos is accused of using the agency's federal firearms license and his relationship with gun manufacturer Sig Sauer to obtain discounted and free guns. He then provided them to high-up agency officials for their personal use, according to whistleblower documents obtained by FoxNews.com and interviews with multiple officials with knowledge of the ongoing probe.

It is unclear, based on the allegations, whether he made money off the alleged transactions, and how many guns were involved.

TSA officials confirmed to FoxNews.com on Friday that Bray did buy weapons from the supervisor, but stressed that he did so legally and with "no knowledge" that they may have been "ill-gotten."

“We are aware of the allegations and we are looking into them," a TSA spokesman said.

Rep. Richard Hudson, R-N.C., chairman of the House Homeland Security transportation security subcommittee, wrote a letter to Transportation Security Administrator head John Pistole on Thursday raising "grave concern" about the claims of possible "gross misconduct."

Though Congress is supposed to be notified of these types of probes, when reached by FoxNews.com for comment, a spokesman for Hudson said they had received no such notification.

In the letter, Hudson cited claims that an Air Marshal supervisor "may have accepted free firearms that were offered because of the employee's official position in 2010, at a time when such firearms were being tested by FAMS for possible future procurement."

He wrote that the same employee "may have, in turn, sold or given those firearms to other Federal employees, including but not limited to the current Director of FAMS."

He also voiced concern that the director's retirement "may be directly related" to the investigation into the activity. Further, he complained that Congress was not notified of any of this.

"I am extremely concerned about recent allegations of unethical behavior involving firearms within the Federal Air Marshal Service, dating as far back as 2010," Hudson told FoxNews.com in a written statement. "The alleged behavior is unbecoming of any official entrusted with the duty to protect and serve the American public. I am outraged at the apparent attempt by TSA and the Federal Air Marshal Service to hide this from Congress. TSA needs to come forward and provide clear and complete answers so that we can conduct a thorough and open review of these alleged activities on behalf of the American people."

Hudson gave Pistole until next Friday to provide more information on whether illegal and/or unethical activity took place and other details.

TSA spokeswoman LuAnn Canipe defended Bray, when asked about the allegations.

"Director Bray has an exemplary record of public service in the federal government," she said. "He has protected presidents and he has protected the traveling public for nearly 40 years."

FoxNews.com attempted to reach Bray for comment via email, but has not received a response.

Reached by phone on Thursday, Poulos told FoxNews.com: "I don't have a comment." Poulos' lawyer also told FoxNews.com it was premature to speak on the record about his client.

The DHS-OIG office said it would not comment on "investigative matters," when reached by FoxNews.com.

The details in Hudson's letter square with accounts from whistleblower documents and other sources.

"The DHS IG is presently investigating a pervasive personal gun purchasing issue at the FAMS. The investigators are quietly calling in federal air marshals that purchased weapons from [the supervisory agent] out of his federal government office and taking photographs of the [sic] each gun's serial numbers," one document obtained by FoxNews.com said.

The document detailing the allegations -- written by a whistleblower and circulated among some employees -- claimed that Poulos, at the Washington Field Office, is "under an active investigation by the DHS IG" for using his FAMS license to buy guns "from Sig Sauer for the FAMS Director, senior TSA/FAMS staff and a few Federal Air Marshals at a discounted 'FAMS Agency' rate."

The document further said "some of these weapons may not fully be accounted for or some stolen -- thus the reason for the DHS IG to want photos of the serial numbers."

Sources and documents say that the director's home was raided on Dec. 26, 2013 and at least one gun was seized that was allegedly connected to the gun operation.

Sources told FoxNews.com that Bray filed a police report after the raid reporting the weapon stolen -- even though it allegedly was seized by ATF during the raid. The Fairfax County police in Virginia, in response to a Freedom of Information Act request by FoxNews.com, provided information saying that on Dec 26, a pistol was reported stolen from the home address of Bray. But the date of theft was listed as Dec. 20.

It is unclear when the DHS OIG investigation began, but if the Dec. 26 stolen weapon police report is any indication, it was going on at that time.

Poulos did not personally have a federal firearms license, but had been authorized to use FAMS' license to purchase guns for the agency, according to documents -- he's accused of using that license to buy the weapons for other officials, including the director, for their personal use.

Documents obtained by FoxNews.com also claim the ongoing investigation "is being conducted quietly to keep Congress in the dark on the gross mismanagement and misdeeds that the FAMS senior management staff have perpetrated for several years."

Texas Republican Rep. John Carter, chairman of the House Appropriations Homeland Security subcommittee, said Friday he was "deeply disappointed and disturbed" by the claims and urged the TSA to provide "clear and comprehensive information" to Congress.

Bray announced his retirement in a March 31 email to agency employees.

"Many of you have heard me talk about the importance of change and how vital it is to keep any agency moving forward," he wrote. "Therefore, I need to practice what I preach and so effective June 28th, I am going to retire from Federal service."

He said he has no plans "except to spend time with my wife and family, without whose love and support I could not have had such a great, long career."

To reach this reporter email jana.winter@foxnews.com

FoxNews.com's Judson Berger contributed to this report.