US intelligence agencies will be given a month to make a formal declaration on whether the Saudi crown prince, Mohammed bin Salman, was responsible for the murder of the Saudi dissident and Washington Post columnist, Jamal Khashoggi.

The annual military spending bill, known as the National Defense Authorization Act (NDAA), was passed by a large majority in the House of Representatives on Wednesday and is expected to be approved by the Senate next week before being signed into law by Donald Trump.

In negotiations before the NDAA’s passage, sections stipulating that Khashoggi’s murderers be subject to punitive measures were stripped from the bill, on the insistence of the White House – as were clauses that would have cut US support for the Saudi war in Yemen.

According to the New York Times, the president’s son-in-law, Jared Kushner, took a leading role in negotiations on behalf of the White House, and was insistent that the punitive clauses on Saudi Arabia should be removed.

But the final version of the bill retained language requiring the director of national intelligence (DNI) to present a formal determination within 30 days on who was responsible for the murder and dismemberment of Khashoggi in the Saudi consulate in Istanbul in October last year.

In April, the US barred entry to 16 Saudis for their role in the murder plot, including one of the crown prince’s closest aides, Saud al-Qahtani. This week, the state department added the former Saudi consul general in Istanbul, Mohammed al-Otaibi.

In a closed-door briefing in December 2018, the CIA director, Gina Haspel, told senators that the agency was convinced the murder had been ordered by the crown prince (colloquially known by his initials MBS).

“We know that the intelligence community has assessed with high confidence that MBS bears at least some responsibility for Khashoggi’s murder and the cover-up that has followed,” Tom Malinowski, the Democratic congressman from New Jersey who drafted the Saudi human rights accountability legislation, told the Guardian. “So if they answer the question, honestly, MBS will be on the list.”

The congressional demand for a formal declaration, will be a test of the independence of the office of the DNI, since the ousting of Dan Coats from the post in the summer. His former deputy, Joseph Maguire, has been acting in the position since August.

“I wouldn’t be surprised if the White House put some pressure on the director of national intelligence to come to a different conclusion,” Malinowski said. “So we’ll be watching this with great interest. We do have the advantage of knowing in advance what the intelligence community thinks because they’ve already told us in a classified setting. So it will be quite striking if they tell us something that is different in response to this.”

Bruce Riedel, a former senior CIA officer and Saudi expert, said that Haspel is likely to have given the agency’s assessment of Prince Mohammed’s role in the Khashoggi murder in verbal form to the Senate, leaving the intelligence community enough wiggle room to hand over a list of the names of suspects the US has already named, excluding the crown prince.

“I’m doubtful [the CIA assessment] was conveyed in a written product. More likely it was in answer to questions,” Riedel said. He added that obscuring the crown prince’s involvement “is going to be a tight line to run, but no doubt this administration will run it”.

He said that the White House would have found it more “problematic” to convince Coats to issue a determination to Trump’s liking.

“The acting DNI is a fine person, but he’s not going to fall on his sword, nor is the director of central intelligence,” Riedel said.