Washington — Lawmakers are pressuring the U.S. intelligence community to publicly identify the individuals it has assessed were involved in the 2018 murder of Saudi dissident and Washington Post columnist Jamal Khashoggi, calling on the Director of National Intelligence to declassify parts of a recent document they say would inform the public without compromising intelligence sources and methods.

A law passed in December mandated that the Office of the Director of National Intelligence (ODNI) submit to Congress a report on Khashoggi's death that included "a list of foreign persons that the Director of National Intelligence has high confidence ... were responsible for, or complicit in ... an act or acts contributing to or causing the death of Kamal Khashoggi."

The report "shall be submitted in unclassified form, but may include a classified annex," one key section of the law reads.

Get Breaking News Delivered to Your Inbox

In late February, ODNI wrote to several House and Senate congressional committees to say neither a public list nor other assessment would be forthcoming.

"Consistent with the protection of sources and methods, the Office of the Director of National Intelligence cannot provide additional information ... at the unclassified level," ODNI wrote in a letter to the Senate Intelligence Committee that was obtained by CBS News. "Nonetheless, we are transmitting under separate cover a classified annex that supplements this letter with additional information."

In a news conference on Tuesday alongside Khashoggi's fiancée, Democratic Senator Ron Wyden of Oregon, who sits on the Senate Intelligence Committee, said he would move forward with invoking a multi-step Senate process to have some of the information made available to the committee publicly released. That process has never been seen through to completion.

"It has now been a year and five months since [Khashoggi] was brutally murdered by the Saudis," Wyden said. "That is far too long to wait for the truth." He accused the Trump administration of orchestrating a "cover-up" to spare Saudi officials embarrassment.

Hatice Cengiz, slain Washington Post columnist Jamal Khashoggi's fiancée, stands alongside Senator Ron Wyden, Democrat of Oregon during a press conference on Capitol Hill on March 3, 2020. SAUL LOEB/AFP via Getty Images

Wyden also said that the Intelligence Committee Chairman Richard Burr, a Republican of North Carolina, and Vice Chairman Mark Warner, Democrat of Virginia, had written a joint letter to ODNI urging that more information about the circumstances of Khashoggi's murder be declassified.

"I think that's fine," Wyden said, but indicated he wanted to take further steps to ensure additional disclosures to the public. He did not directly address questions about Republican support for using the Senate mechanism he planned to invoke.

House Intelligence Committee Chairman Adam Schiff, Democrat of California, also wrote last week to Acting DNI Richard Grenell to specifically request the declassification of the annex, which Schiff said could be publicly released "with appropriate redaction."

"[T]here is a robust body of credible unclassified reporting ... related to the killing of Mr. Khashoggi," Schiff wrote, pointing to a U.N. report released last year that said there was "credible evidence" that Crown Prince Mohammed bin Salman, known as MBS, and other senior Saudi officials were responsible for Khashoggi's death.

"The Committee, therefore, does not foresee that any harm to U.S. national security would result from immediately declassifying the findings contained in DNI's classified annex, with redactions as necessary," Schiff wrote.

A U.S. official familiar with the contents of the annex confirmed that the document names MBS in connection with Khashoggi's murder. The Washington Post first reported on the annex's contents.

The CIA assessed that the crown prince ordered Khashoggi's killing, though no direct evidence immediately arose linking MBS to Khashoggi's death, U.S. officials confirmed to CBS News in 2018. Saudi officials have consistently denied Mohammed knew of the plot.

In 2018, the U.S. issued sanctions on 17 Saudi individuals it alleged were involved in Khashoggi's death, through neither MBS nor a top Saudi official implicated in the murder by Saudi Arabia's top prosecutor was on that list. Secretary of State Mike Pompeo has said several times that the U.S. would hold the individuals responsible for the killing accountable.

President Trump has resisted blaming MBS for any part of the plot and called Saudi Arabia a "spectacular ally." He vetoed three resolutions passed last year by Congress to stop arms sales to the Kingdom.

A prominent critic of the crown prince, Khashoggi was killed at the Saudi consulate in Istanbul on October 2, 2018. In a closed trial last year, Saudi Arabia charged 11 individuals with the murder, issuing death sentences for five of them. None were identified publicly.

An ODNI spokesperson said Tuesday the agency believed its response in February had already satisfied Congress' requests and maintained it could not make intelligence about the matter public.

"That is something that cannot be done without jeopardizing sources and methods," the spokesperson said. "The Intelligence Community has a legal and moral obligation to protect classified information and ensure sources and methods are not jeopardized."

Democratic Congressman Tom Malinowski of New Jersey, who appeared alongside Wyden at Tuesday's event, pushed back on ODNI's justification.

"That's not enough under the law to simply assert that this would be bad for our national security or would compromise sources and methods. You have to explain why, and how," Malinowski said.

"You can name somebody — you can say, 'You are responsible for this crime' — without revealing the methods that you may have used to determine that responsibility," he said. "That's not an excuse, and they know it."