In an interview with The Washington Post late Saturday, Trump backed down from his assertion that Saudi Arabia's account of the circumstances surrounding Khashoggi's death at the country's Turkish consulate was credible.
"Obviously there's been deception and there's been lies," Trump said. "Their stories are all over the place."
Khashoggi, a U.S. resident and Washington Post contributing columnist, has not been seen since visiting the Saudi consulate Oct. 2 to get documents for his planned marriage.
Saudi Arabia initially said Khashoggi left the embassy unharmed although security camera footage captured his entry, but not his exit, but on Friday confirmed he was killed in a brawl at the consulate.
"First we were told Mr. Khashoggi supposedly left the consulate and there was blanket denial of any Saudi involvement. Now, a fight breaks out and he's killed in the consulate, all without knowledge of Crown Prince," Graham wrote on Twitter. "It's hard to find this latest 'explanation' as credible.
Saudi Foreign Minister Adel Al-Jubeir told Fox News' Bret Baier the country is investigating Khashoggi's death and the 18 people suspected of being involved would be punished apporpriately.
"This was an operation that was a rogue operation," he said. "This was an operation where individuals ended up exceeding the authorities and responsibilities they had. They made the mistake when they killed Jamal Khashoggi in the consulate and they tried to cover up for it."
Khashoggi's friends have demanded Saudi Arabia provide his body for a funeral and Turkish officials believe he was dismembered and say there are audio and video recordings as proof.
Trump told The Washington Post he was aware of the claims that recording of the events inside the consulate existed, but he hasn't been given the opportunity to review such recordings.
"I've heard all about the videos or the tapes. Nobody would get it faster than me. Nobody has been able to show it," he said.
"We are looking for justice here and this will be revealed in all its naked truth, not through some ordinary steps but in all its naked truth," Erdogan said.
Trump said he didn't believe Saudi Arabia's Crown Prince Mohammed bin Salman should be replaced, adding he hasn't received information that he was responsible for Khashoggi's death and his father, King Salman "does not know about it."
"Nobody has told me he's responsible. Nobody has told me he's not responsible. We haven't reached that point. I haven't heard either way," he said. "There is a possibility he found out about it afterward. It could be something in the building went badly awry. It could be that's when he found about it. He could have known they were bringing him back to Saudi Arabia."
Trump added it was too early to say how or if he would sanction Saudi Arabia, noting the country's history of purchasing military equipment from the United States and assisting U.S. operations in the Middle East.
"I would love if he wasn't responsible," Trump said. "I think it's a very important ally for us. Especially when you have Iran doing so many bad things in the world, it's a good counterbalance to the world. Iran, they're as evil as it gets. They're probably laughing at this situation as they see it. Iran is as evil as it gets."
"It would be premature to comment on sanctions and premature to comment on really any issues until we get further down the investigation and get to the bottom of what occurred," he said.
Mnuchin said will participate in a meeting in Riyadh this week to combat terrorism financing with government officials from Saudi Arabia and other Middle East partners.