Khashoggi, a U.S. resident and Washington Post columnist, was killed in the Saudi consulate in Istanbul on October 2, sparking global outrage against the kingdom and its de facto ruler, Crown Prince Mohammed bin Salman. They added: "We have and continue to hear various theories without seeing the primary basis for these speculations".
The assessment was based largely on circumstantial evidence relating to the prince's central role in running the Saudi government.
"He told me that he had nothing to do with it", Trump said, adding that "many people" also said the crown prince had no knowledge of the killing.
The president also said: "Will anybody really know?'" "Recent reports indicating that the USA government has made a final conclusion are inaccurate", State Department spokeswoman Heather Nauert said in a statement on Saturday.
Prince Mohammed was not implicated in the murder, a spokesman for the prosecutor said.
Khashoggi, a journalist for WaPo, was brutally killed after he entered a Saudi consulate in Turkey on October 2. "And, we will do that while maintaining the important strategic relationship between the United States and Saudi Arabia", Nauert underlined.
Trump has repeatedly made it clear that he doesn't want to see the Khashoggi murder threaten United States arms sales to the Saudis.More news: Don't trade sovereignty for cash, Pence says in swipe at China
"The United States government is determined to hold all those responsible for the killing of Jamal Khashoggi accountable", the State Department said in a statement.
"If he is going to be the face of Saudi Arabia going forward, I think the kingdom will have a hard time on the world stage", he told NBC.
Khashoggi was killed October 2 in the Saudia consulate in Istanbul, where he went to pick up documents that he needed to marry his fiancee, who lives in the Turkish city.
Khashoggi, 59, who wrote for The Washington Post, was killed last month inside the Saudi Consulate in Istanbul where he had gone to collect papers related to his marriage.
Khalid bin Salman denied the allegation via Twitter soon after the Post published its article. There's no reason for me to hear it.
He pushed for Riyadh to disclose the location of Khashoggi's remains and called for the suspects to be tried in Turkey.
The U.S. Department of the Treasury's Office of Foreign Assets Control on Thursday imposed sanctions on 17 individuals over their alleged roles in the killing of Khashoggi. Since the agency is aware that Mohammed Bin Salman is teflon inside Saudi Arabia, it seems probable that the target of the leak is in the US.