Jameel Jaffer is the executive director of the Knight First Amendment Institute at Columbia University. Joel Simon is the executive director of the Committee to Protect Journalists. The opinions expressed in this commentary are solely those of the authors. View more opinion articles on CNN.

(CNN) From the moment journalist Jamal Khashoggi was executed in the Saudi Arabian consulate in Istanbul in October, President Donald Trump has been running interference for the Saudi government and its crown prince, Mohammed bin Salman. He has baselessly attributed Khashoggi's killing to rogue actors, denigrated the value of investigations and amplified the prince's self-serving denials. Trump has shown himself so willing to cover for the prince that late last year the Senate felt compelled to pass an extraordinary resolution that directly condemned the monarch-in-waiting for the murder.

But with the president seemingly committed to shielding those responsible for this appalling crime, condemnation is not enough. Human rights and press freedom organizations have called on Turkey to ask UN Secretary-General Antonio Guterres to conduct a full investigation into the killing, and US legislators should support that call. At the same time, Congress and the US courts should require the executive branch to release files that show what, if anything, the administration knew about Saudi plans to harm the journalist, what the intelligence agencies have since learned about his murder and whether the White House is acting in concert with the Saudi regime to protect the perpetrators.

On Thursday, the Committee to Protect Journalists joined a lawsuit filed by the Knight First Amendment Institute at Columbia University, which asked a federal court in Washington DC to compel the government to release some of these files. Information already in the public domain paints a damning picture of the Kingdom's actions. US intelligence agencies told The New York Times that they intercepted communications between Saudi officials planning a possible ruse. The 15-man team sent from Riyadh included several members of the Saudi military and at least four close associates of the crown prince. Reports indicate that most of the team likely traveled to Istanbul on private jets linked to the royal family.

A gruesome audiotape of the murder captures one of the Saudi operatives saying over the phone , "Tell yours, the thing is done, it's done," which CNN's source interpreted as referring to a superior or boss. Given the crown prince's close hold on power in the kingdom, the "boss" in this context was almost certainly the prince himself or someone very close to him.

And yet President Trump was quick to defend bin Salman at the outset and has stood resolutely by his decision . After a phone call with King Salman just days after the killing, Trump told the media that he didn't think the king or his son knew anything about Khashoggi's disappearance. "His denial to me could not have been stronger," Trump declared . "I don't want to get into [the king's] mind, but it sounded to me like maybe these could have been rogue killers," Trump added, with no evidence.

Trump also undercut the investigation conducted by the CIA, which reportedly concluded that the crown prince had ordered the murder , despite the Kingdom's denial of this. "We may never know all of the facts surrounding the murder," the White House announced in a bizarre official statement in November. "It could very well be that the Crown Prince had knowledge of this tragic event — maybe he did and maybe he didn't!" This was followed by The New York Times reporting that Jared Kushner, the president's son-in-law and special advisor, offered the crown prince guidance on " how to weather the storm " after Khashoggi's death.

Against this background, the public interest in disclosure far outweighs the executive interests that might ordinarily justify secrecy. This is why investigating if the US knew anything about the murder or previous threats to Khashoggi's life and, if so, whether they took any steps to warn him, is imperative. (A directive issued in 2015 generally requires US intelligence agencies to warn individuals when they learn of threats to their life or liberty.)

Others are seeking additional pieces of the puzzle. The Open Society Foundation's Justice Initiative filed a suit under the FOIA seeking the release of intelligence files about the killing itself, including the CIA assessment tracing the plot to the crown prince. Legislators have sought these documents and others as well.

Disclosure of these files could do much more than shed light on what happened that horrible day in October. It could help us better understand why President Trump has aligned himself in opposition to those who have decried the killing and demanded that the Saudi regime be held to account for it. The documents could also allow us to better evaluate any action that the Trump administration may take under the Global Magnitsky Act, which, having been triggered by Senate leaders last year, requires the administration to investigate Khashoggi's killing, identify those responsible for it, and consider the imposition of sanctions. (The administration's response under the act must be made to the Senate Committee on Foreign Relations by Feb. 7 .)

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