New information revealed from a lawsuit against the government for its handling of Hillary Clinton's emails shows that the Federal Bureau of Investigation "primarily" relied on consensual access, or asking Clinton and her aides' permission to view evidence.

The FBI released a previously undisclosed declaration filed in federal court Wednesday evening. The declaration contains new information regarding grand jury subpoenas issued in the investigation into Clinton's private server.

Watchdog groups Cause of Action and Judicial Watch successfully convinced a federal judge to order the release of the declaration submitted ex parte and in camera in the civil case by E.W. Priestap, who supervised the Clinton investigation at the FBI. Cause of Action and Judicial Watch are suing the State Department and National Archives for violations of the Federal Records Act, for failing to properly preserve Clinton's emails.

Priestap's declaration was a supplemental filing related to the grand jury subpoenas and was only seen by federal judge James Boasberg and the government's lawyers. The newly released declaration does not reveal the exact language of the grand jury subpoenas that were issued in the case, making it difficult to decipher the specific actions taken by the FBI.

Priestap's declaration, however, reveals grand jury subpoenas were issued to wireless companies that operated Clinton's BlackBerry and to "private third party e-mail accounts" of individuals who corresponded with Clinton.

The use of grand jury subpoenas indicates the investigation was criminal in nature and not a security review that the Clinton presidential campaign claimed, or a "matter" rather than an investigation, which was used by former FBI director James Comey in describing the case.

"Americans are finally getting important information about the FBI's efforts to recover the government emails possessed by Hillary Clinton," said John J. Vecchione, president and CEO of Cause of Action. "It's amazing that this information was only revealed by this suit and not by Congress, the mainstream press, or the administration."

The declaration shows the FBI was primarily asking permission to obtain emails from Clinton and her team, and not through search warrants. The bureau claimed it had difficulty proving probable cause that classified material was contained on various email accounts and devices associated with the Clinton server.

"FBI sought to obtain all identified e-mail communications that were transmitted or stored upon former Secretary Clinton's private email servers," Priestap writes in the declaration, which was originally filed in April. "These investigative efforts consisted of obtaining e-mail repositories through consent of former Secretary Clinton, her representatives, former members of her staff, the State Department, and numerous other government agencies with which the Secretary communicated."

Priestap, whose official FBI role is assistant director assigned to counterintelligence and counterespionage matters, explains the methods the FBI used to recover emails from Clinton's two BlackBerry accounts. Clinton used the accounts hr15@mycingular.blackberry.net and hr15@att.blackberry.net during her first eight weeks as secretary of state.

"During the course of the FBI's investigation, limited e-mail communications during the period of January 21, 2009 through March 18, 2009 for the two e-mail accounts in question were obtained and have since been turned over to the Department of State for agency record determination," Priestap writes. "The FBI utilized numerous investigative methods to obtain any remaining BlackBerry e-mails from January 1, 2009 through March 18, 2009, to include primarily seeking consensual access to any e-mail repositories and obtaining personal electronic devices used by former Secretary Clinton which may have contained relevant e-mails."

Comey previously said consensual access was used when dealing with Clinton's aides who were lawyers, arguing informal agreements are faster than issuing subpoenas, which could be delay through the legal process.

Previous reporting revealed that the FBI never asked for the mobile devices and computers used by Clinton's aides while they were at the State Department.

The FBI never gained access to any of 13 mobile devices used by Clinton that were tied to her private email account. An aide destroyed at least two of Clinton's phones by smashing them with a hammer.

The only computers used by aides the FBI recovered were two used after Clinton had left the State Department. The FBI gave partial immunity deals to aides Cheryl Mills and Heather Samuelson in exchange for laptops they used in 2014. At least five individuals connected to Clinton received immunity deals from the FBI.

"It is my opinion that the FBI undertook all reasonable and comprehensive efforts to recover e-mail communications relevant to its investigation of the potential unauthorized transmission and storage of classified information of the personal e-mail server of former Secretary Clinton," Priestap wrote.

Grand jury subpoenas that were issued in the case went to cellular service providers that operated Clinton's BlackBerry device between January 21, 2009 and March 18, 2009, when Clinton stopped using the BlackBerry accounts and relied on the private server that hosted the email address hdr22@clintonemail.com.

"Specifically, the FBI served Grand Jury subpoenas on Research in Motion Limited (RIM), the maker of BlackBerry electronic devices; Cingular Wireless and its successor AT&T Wireless, both of which provided mobile phone service and therefore data access; and another service provider, which at the time provided the e-mail service utilized by former Secretary Clinton," Priestap wrote.

Priestap said the subpoenas asked for customer account information and transaction information from the emails including only the to, from, and subject fields, and not the content of the actual emails.

Priestap suggested the FBI did not establish probable cause to issue a search warrant that would be necessary to receive the contents of the emails from the cellular providers. Priestap cited U.S. law governing electronic communications that prohibits receiving such information without a search warrant.

"The information sought consisted generally of electronic communications transaction information (i.e., to/from/headers/subject lines of e-mails) but no content," he wrote. "Consistent with 18 U.S.C. 2703, the FBI cannot request content via a grand jury subpoena, and would instead have had to establish probable cause to obtain any search warrant."

The declaration states that the wireless companies did maintain Clinton's BlackBerry accounts but "confirmed that electronic communications transaction information for the accounts was no longer retained by the respective companies and, therefore, the service providers were unable to produce additional information to the FBI for either account."

Priestap said the FBI's use of the legal process, such as issuing grand jury subpoenas, was "limited due to the scope of the investigation and the need to establish that sufficient probable cause existed to believe classified e-mails resided within any identified e-mail account, computer, cellular or wireless mobile device, or other electronic device of investigative interest in order to obtain any search warrant."

The FBI was able to demonstrate probable cause to obtain a search warrant for emails associated with the Clinton server found in October 2016 on a computer shared by Anthony Weiner and Huma Abedin, Clinton's close aide. Those emails were discovered in a separate FBI investigation into Weiner's sexting with an underage girl.

The new declaration shows the FBI was also able to establish "sufficient probable cause" to issue additional grand jury subpoenas to holders of third party email accounts who communicated with Clinton. Those individuals, however, are not named in Priestap's declaration.