"I have zero question in my mind that the crown prince directed the murder ... zero question", Corker said.
"There's not a smoking gun, there's a smoking saw", Sen.
The senator also says he can not support arms sales to Saudi Arabia so long as the crown prince is in charge.
Making some of their strongest accusations so far, both Republicans and Democrats said they still wanted to pass legislation to send a message to Saudi Arabia that the United States condemned the death of Khashoggi.
Khashoggi, a USA resident who wrote for the Washington Post, was killed inside the Saudi consulate in Istanbul in October.
In remarks after a briefing from CIA Director Gina Haspel, Senate Foreign Relations Committee Chairman Bob Corker, R, and Senator Lindsey Graham, R, suggested there is no plausible way that Saudi Crown Prince Mohammed bin Salman didn't order the killing of Khashoggi, a Washington Post contributing columnist, and said that the evidence is overwhelming.
Tuesday's briefing comes as the Senate weighs punishing the longtime Middle East ally over the killing.
Despite the CIA's assessment, President Donald Trump has repeatedly dismissed it, calling it premature. Legislators have vowed to punish Saudi Arabia, proposing a measure which would remove US support for the Saudis in the civil war in Yemen.
CIA Director Gina Haspel will give a closed briefing to leaders of several US Senate committees after she failed to take part in a Senate briefing by Trump administration officials on Jamal Khashoggi's killing.
Sen. Bob Corker says a jury would find the Saudi crown prince 'in about 30 minutes.'
A Saudi government critic who was living in self-imposed exile in the US, Khashoggi was killed inside the Saudi consulate in Istanbul on 2 October.
The senators said Haspel's briefing contradicted information from Trump, as well as Secretary of Defense James Mattis and Secretary of State Mike Pompeo. Trump said in a statement on November 20.
USA intelligence officials have concluded that the crown prince must have at least known of the plot, but Trump has been reluctant to pin the blame.
The president has been briefed by the Central Intelligence Agency, but his takeaway was dramatically different from that of the senators.
"And yet we have to have a relationship with these individuals or with these countries".
Senators are "trying to figure out an amendment that a larger group of people could get behind that addresses this issue without undermining our national interests", Corker said.
Graham said he would not vote for the Yemen resolution.
"I'm not going to destroy the world economy and I'm not going to destroy the economy for our country by being foolish with Saudi Arabia", Trump said at the time. "It is my hope that the Senate will act and send a strong, unequivocal message that such actions can not stand and I believe that my legislation with Senator Graham is the appropriate response".