The attorney for a former State Department arms expert accused of leaking classified information to a Fox News reporter wrote in newly released court filings that other high-level government officials may have been responsible for the illegal disclosure.

Defense attorney Abbe Lowell questioned the reliability of the government’s evidence and said national security officials other than his client, Stephen Kim, may have communicated with Fox News correspondent James Rosen in the hours before Rosen published a controversial story on the North Korean nuclear program.

The behind-the-scenes battle between Kim’s attorneys and federal prosecutors in the high-profile­ leak case became public Thursday when redacted copies of a trove of court filings were posted online. The legal maneuvering provides more detail about information the government gathers in leak investigations, including e-mails between a second Fox News reporter and a former national security adviser who is now President Obama’s chief of staff.

Kim is fighting charges in the District’s federal court that he disclosed national defense information in violation of the 1917 Espionage Act. The Justice Department has never prosecuted a reporter under that law. But the investigation into Kim attracted attention because a search warrant for Rosen’s personal e-mails suggested his reporting techniques made him a possible co-conspirator. The disclosure followed reports about a separate leak probe in which the Justice Department secretly seized phone records of Associated Press journalists.

At issue in the Kim case is a story Rosen wrote in June 2009 about warnings from U.S. intelligence sources about North Korea’s likely response to a U.N. resolution condemning its nuclear tests. Rosen’s story appeared hours after a top-secret report spelled out to a limited circle in the intelligence community that the CIA had learned of additional tests from“sources inside North Korea.”

About an hour before the story was published online, the new court documents show, former Fox News reporter Major Garrett e-mailed former deputy national security adviser Denis McDonough to tell him that he would “receive a call or an e-mail from a trustworthy colleague, James Rosen,” who “has some very good stuff on North Korea and would like some [National Security Council] guidance.”

McDonough responded two minutes later, according to the court filing, “[g]ot it.”

Ten minutes after that, Rosen called a number associated with McDonough, according to court documents, that was also accessible to former counterterrorism adviser John Brennan, now CIA director, and former deputy national security adviser for operations, Mark Lippert, now an assistant secretary of defense.

Rosen’s phone records show someone from that number returned the call and spoke with him for several minutes, according to the court filing.

“No one at the NSC remembers that call,” according to an FBI internal report referenced in the court filing.

All three officials have denied being the source of the leak, and there is no evidence, prosecutors said, that any of them read the report before the publication of Rosen’s article. Federal prosecutors in their response characterized Kim’s request as a “transparent attempt to drag three former senior White House officials into this matter based on rank speculation.”

The government’s response to the suggestion that Rosen talked with someone in the NSC office that day, however, is largely redacted.

Kim’s attorney has criticized the government for criminalizing exchanges between reporters and government officials that he has said “happen hundreds of times a day in Washington.” Kim is being prosecuted for the “unauthorized” disclosure of classified information, and in the court documents initially filed in February, Lowell said he was trying to determine to what extent officials like McDonough “were in fact authorized to speak to the press on these issues.”

The case against Kim, which is unlikely to go to trial before early 2014, relies on phone, computer and security-badge records. Prosecutors said someone who had logged in with Kim’s user profile viewed the classified report “at or around” the same time calls were placed from his desk phone to Rosen. Investigators also tracked how Kim and Rosen moved in and out of the State Department headquarters at similar times in the hours before the story appeared online. Prosecutors quote from ­e-mails that show Kim and the reporter using aliases to communicate on personal accounts.

But Lowell argued that the government has not “produced any e-mail, text message, or recorded conversation documenting the contents of any communication between Mr. Kim and Mr. Rosen on that date.” The government’s case, he wrote, relies on the finite number of people who both read the report before the story was posted and also communicated with Rosen that day.

Part of Kim’s defense, Lowell said, “will be the inherent unreliability of the government’s efforts to account for all of those who accessed the intelligence report at issue.” That number, Lowell said, has grown from 78 to 168 in the course of the investigation.

Lowell specifically requested information about other apparent leaks of intelligence to Fox during the same period because “it tends to prove that someone other than Mr. Kim was actively leaking intelligence to Fox News.”

In addition, he requested information about investigations into other officials, including the three former national security advisers, who may have had access to the top-secret information and may have been in contact with Rosen that day.

U.S. District Judge Colleen ­Kollar-Kotelly found Kim’s requests “too broad,” but she said she would consider more narrow requests seeking specific information about investigations into other possible leaks to Fox and those into the three former national security officials.

Kollar-Kotelly wrote that the defendant “produced persuasive circumstantial evidence that three NSC officials may have learned of the intelligence purportedly disclosed to Mr. Rosen, and there is evidence to suggest at least one of those officials had contact with Mr. Rosen on the day in question prior to the publication of the Rosen article.”

“In combination, this evidence may be sufficient to require the government to produce to the defendant information regarding investigations into these officials for unauthorized disclosure of information regarding North Korea, or disclosures to Fox News.”