Hillary Clinton hired a Connecticut company to back up her emails on a “cloud” storage system, and her lawyers have agreed to turn whatever it contains over to the FBI, a personal familiar with the situation said Tuesday.

The disclosure came as a Republican Senate committee chairman, Wisconsin Sen. Ron Johnson, also asked the firm to turn over to the committee copies of any Clinton emails still in its possession.

There were conflicting accounts as to whether the development could lead to recovery of any of Clinton’s more than 31,000 personal emails, which she said she deleted from her private server upon turning over her work-related emails to the State Department, at its request, in December 2014.

Congressional Republicans have voiced skepticism as to whether the 30,940 business emails that the Democratic presidential candidate handed over represented all of those related to her position as secretary of state. The FBI is separately investigating whether Clinton’s arrangement put classified information at risk but has yet to characterize it as a criminal inquiry.

Datto Inc., based in Norwalk, Conn., became the second data storage firm to become entangled in the inquiry into Clinton’s unusual email arrangement, which has sparked a furor that has dogged her campaign. In August, Clinton and the firm that had managed her server since June 2013, Colorado-based Platte River Networks, agreed to surrender it for examination by the FBI.

On Friday, Clinton’s attorney, David Kendall, and Platte River agreed to allow Datto to turn over the data from the backup server to the FBI, said the person familiar with Datto’s storage, who spoke on condition of anonymity because of the sensitivity of the matter.

Datto said in a statement that “with the consent of our client and their end user, and consistent with our policies regarding data privacy, Datto is working with the FBI to provide data in conjunction with its investigation.”

The source said, however, that Platte River had set up a 60-day retention policy for the backup server, meaning that any emails to which incremental changes were made at least 60 days prior would be deleted and “gone forever.” While the server wouldn’t have been “wiped clean,” the source said, any underlying data likely would have been written over and would be difficult to recover.

Since Clinton has said she deleted all of her personal emails, the configuration might complicate any attempt by FBI forensics experts to resurrect emails from the backup. However, Bloomberg reported recently that the FBI has recovered some of Clinton’s emails, apparently from the server they seized from Platte River.

In laying out facts gathered by the Senate Homeland Security and Governmental Affairs Committee, which he chairs, Johnson offered the first public confirmation that Clinton or her representatives had arranged for a backup of her email server after she left office in early 2013.

His letter also cited internal emails recounting requests in late 2014 and early 2015 from Clinton representatives for Colorado-based Platte River Networks, the firm managing Clinton’s primary server, to direct Datto to reduce the amount of her emails it was backing up. These communications led a Platte River employee to air suspicions that “this whole thing really is covering up some shaddy (sic) shit,” according to an excerpt of an email cited by Johnson.

The controversy seems sure to come up on Oct. 22, when Clinton is scheduled to testify to a House committee investigating the fatal 2012 attacks on U.S. facilities in Benghazi, Libya. It was the panel’s chairman who first declared last March that she had “wiped” her server clean based on a letter from Clinton’s attorney.

Spokesmen for Clinton’s campaign declined to respond to requests for comment about Johnson’s letter Tuesday.

On May 31, 2013, four months after Clinton left office, the Clinton Executive Service Corp., which oversaw her email server contracts, hired Platte River to maintain her account. Its New Jersey-based server replaced the server in her New York home that had handled her emails throughout her tenure as secretary of state.

Several weeks ago, Platte River employees discovered that her private server was syncing with an offsite Datto server, he said.

When Datto acknowledged that was the case, a Platte River employee replied in an email: “This is a problem.”

Johnson said that “Datto apparently possessed a backup of the server’s contents since June 2013.”

Upon that discovery, Platte River “directed Datto to not delete the saved data and worked with Datto to find a way to move the saved information . . . back to Secretary Clinton’s private server.”

The letter also noted that Platte River employees were directed to reduce the amount of email data being stored with each backup. Late this summer, Johnson wrote, a Platte River employee took note of this change and inquired whether the company could search its archives for an email from Clinton Executive Service Corp. directing such a reduction in October or November 2014 and then again around February, advising Platte River to save only emails sent during the most recent 30 days.

Those reductions would have occurred after the State Department requested that Clinton turn over her emails.

It was here that a Platte River employee voiced suspicions about a cover-up and sought to protect the company. “If we have it in writing that they told us to cut the backups,” the employee wrote, “and that we can go public with our statement saying we have had backups since day one, then we were told to trim to 30 days, it would make us look a WHOLE LOT better,” according to the email cited by Johnson.

In the letter to Austin McChord, Datto’s CEO, Johnson asked the firm to produce copies of all communications it had relating to Clinton’s server, including those with Platte River and the Clinton firm.” He also asked whether Datto and its employees were authorized to store and view classified information and for details of any cyberattacks on the backup server.

In an ongoing review of Clinton’s work emails, the State Department and intelligence agencies have found more than 400 containing classified information, including at least two declared “Top Secret,” the most sensitive national security data. Clinton has said none of the emails were marked classified during her tenure although some communications by their nature are classified at creation.

In other developments, the State Department is asking Clinton to search again for any emails, regardless of format, from the first two months of her tenure, according to a document filed Tuesday by the State Department in response to a lawsuit about her emails.

The request to Clinton attorney David Kendall, dated Oct. 2, comes weeks after the State Department obtained a series of emails that Clinton did not turn over despite her claim that she sent the agency all her work-related correspondence.

The chain of emails, dating from Jan. 10, 2009 to Feb. 1, 2009, were exchanged with former Gen. David Petraeus when he headed the military’s U.S. Central Command, responsible for running the wars in Iraq and Afghanistan and mostly relate to personnel matters.

“These emails are now in our possession and will be subject to Freedom of Information Act requests,” State Department spokesman John Kirby said last week. “Furthermore, we asked the IG to incorporate this matter into the review Secretary Kerry requested in March. We have also informed Congress of this matter.”

Clinton said she was unable to turn over emails she sent or received from late January to March 18, 2009, because she continued to use the AT&T Blackberry account she had when she was a senator. But after the Petraeus emails surfaced and showed she had not turned over emails sent or received on her new account, aides said said she could not turn over emails because they had not been captured on her private server.

Clinton’s campaign and Kendall did not immediately respond to questions about Johnon’s letter or the State Department’s new request.