There was some confusion inside the U.S. Embassy in Riyadh before Jared Kushner arrived in Saudi Arabia in February. Washington was still reeling from the grisly murder of Jamal Khashoggi, which had thrown an unexpected wrench into an already tense U.S.-Saudi relationship, and diplomats were still navigating the aftershocks. Ordinarily, embassy staff would be intimately involved in organizing the details of such a trip. But Kushner’s schedule with Saudi Crown Prince Mohammed bin Salman was largely a mystery. In fact, a source familiar with the planning told me, the royal court, not the U.S. Embassy, was arranging Kushner’s itinerary. According to the source, an embassy notetaker was also not present in Kushner’s meetings with King Salman and the crown prince, nor was the embassy briefed on what the president’s son-in-law discussed behind closed doors.

The semi-surreptitious visit is the most recent of several remarkable episodes involving Kushner that are now being investigated by congressional Democrats. Their guiding hypothesis is that Kushner’s diplomatic naïveté and close relationship with bin Salman, better known as M.B.S., might put U.S. national security at risk. “I’m not only troubled—I am stunned by the friendship,” Massachusetts Congressman Jim McGovern told me. “It looks bad. It smells bad. It is bad.”

The Kushner-M.B.S. bromance, which has been a source of intrigue and consternation dating back to the earliest days of Donald Trump’s presidency, is of particular interest to Congressman Eliot Engel, the chairman of the House Foreign Affairs Committee. At the end of last month, Engel sent a letter to Secretary of State Mike Pompeo requesting documents and records related to Kushner’s February trip to Saudi Arabia, including any “handwritten notes” related to any meetings attended by Brian Hook, the sole State Department official included in Kushner’s delegation. The goal, a congressional staffer told me, is to glean any insight into what Kushner discussed with M.B.S. and other foreign officials.

The State Department missed the deadline this past Friday to provide the information and documents requested by the committee, according to the first congressional source. In a statement to the Daily Beast, which first reported that the U.S. Embassy in Riyadh had been left in the dark about Kushner’s trip, a senior administration official said, “This reporting is not true, and the sources are misinformed.”

On Capitol Hill, however, concerns about Kushner’s diplomatic freelancing are widespread. “I think people deal with him because he is the president’s son-in-law,” a second congressional aide told me. But that familial back channel to Trump also leaves the U.S. government vulnerable. As The New York Times has reported, M.B.S. marked Kushner early on as a potentially malleable asset for advancing Saudi interests in Washington. “[Trump’s] inner circle is predominantly deal makers who lack familiarity with political customs and deep institutions, and they support Jared Kushner,” a delegation of Saudi officials, sent to the U.S. in November 2016, wrote in a slide presentation obtained by the Lebanese newspaper Al Akhbar. The Saudi crown prince later boasted that he had Kushner “in his pocket,” according to the Intercept.

“No one is impressed that he is friends with M.B.S. No one cares. It is a bad thing,” the second congressional aide said, adding that Kushner’s trust in the crown prince makes him look “completely out of his depth.” Shortly after Kushner’s first surprise trip to Saudi Arabia, for instance, in October 2017, M.B.S. initiated a sweeping crackdown on his political rivals, imprisoning more than 30 Saudi elites at the Ritz-Carlton, reportedly torturing some of them, and allegedly kidnapping Lebanese Prime Minister Saad Hariri. (The Saudi government has denied allegations of torture and abuse during the “anti-corruption proceedings.”) Defenders of the U.S.-Saudi alliance, including Kushner, Trump, and Pompeo, argue that these are the realpolitik costs of containing Iran and resolving the Israeli-Palestinian conflict. But critics of the administration say the White House is getting played. “[A relationship with M.B.S.] does not mean that you are going to be the guy who is going to bring Middle East peace,” the congressional aide said. “It is an embarrassment.”