The office of Istanbul's prosecutor on Wednesday issued an arrest warrant for two Saudi officials for their alleged links to the murder of journalist Jamal Khashoggi at the kingdom's consulate in Turkey.
US Senator Bob Corker, the current head of the Senate Committee on Foreign Relations, also said he is certain that MBS ordered Khashoggi's murder. Graham said "you have to be wilfully blind" not to conclude that this was orchestrated and organized by people under the crown prince's command.
The crown prince is "crazy" and "a wrecking ball" who is "complicit in the murder of Mr Khashoggi to the highest level possible", Graham said in withering criticism of an American ally.
Erdogan has said that solving the Khashoggi killing would also be in the interest of the Saudi monarchy.
USA intelligence assessments and experts say it's unlikely the killing could have happened without the crown prince's knowledge.
Ahmed al-Asiri acted as deputy intelligence chief of Saudi intelligence services, and al-Qahtani a Saudi royal court advisor.
Some of the most important evidence may be an audio recording of the murder that Turkey said it has distributed.
Graham said he would not vote for the Yemen resolution.
"Before this briefing, I was convinced that we had to take steps on the war in Yemen and I believe that we had to take steps on the Saudis", Menendez said.
Central Intelligence Agency chief Haspel to brief Senate on Khashoggi killing
Mr Khashoggi, a U.S. resident who wrote for the Washington Post, had been a fierce critic of the crown prince before his death. The CIA reportedly believes Prince Mohammed is responsible, as do many U.S. politicians, but not President Donald Trump .
Khashoggi, a Washington Post columnist and a critic of the Saudi Arabian Crown Prince, was killed inside the consulate after he went there on October to collect documents in order to marry his Turkish fiancée.
Under mounting pressure from lawmakers who wanted action against Riyadh, Mattis and Secretary of State Mike Pompeo told senators there was no direct evidence linking the crown prince to the murder.
On Wednesday, he elaborated by saying that he urged Prince Mohammed to provide the world with "better answers".
"I do believe that it's really needed in terms of ensuring what really happened and who are the responsible for that very bad killing".
Khalid's return to the US comes just one day after a closed US Senate briefing by Central Intelligence Agency chief Gina Haspel.
Last week, 14 of Trump's fellow Republicans, who hold a slim majority in the Senate and rarely break from the president, defied his wishes and voted with Democrats to advance the measure that would end US support for the Saudi-led war effort in Yemen. But the Senate could vote to end that arms sale or end United States support of Saudi Arabia's war in Yemen.
Asked if he's spoken to the White House about the push, Graham said bluntly: "They know where I'm at".
Renowned Hollywood actor and filmmaker Sean Penn has arrived in Istanbul to shoot some scenes for his upcoming documentary about the killing of Saudi journalist Jamal Khashoggi, the Turkish newspaper Hurriyet reported.