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.
A Saudi operative then reportedly donned Mr Khashoggi's clothes and left the consulate.
Crown Prince Mohammed bin Salman was allegedly not aware of the operation beforehand, according to the top diplomat. "I might know a lot by Monday". He also said he will talk soon to Prince Mohammed. However, pro-government newspapers have been leaking information about Khashoggi's killing, apparently with the help of Turkish security forces.
Officials in Saudi Arabia have not answered repeated requests for comment from The Associated Press in recent days, including on Monday.
Mutreb's name also matches that of a first secretary who once served as a diplomat at the Saudi Embassy in London, according to a 2007 list compiled by the British Foreign Office.
President Trump said Saudi Arabia's announcement that suspects were in custody marked a "good first step", though some USA lawmakers on both sides of the aisle hav said Saudi Arabia's account isn't credible and seems created to exonerate Crown Prince Mohammed bin Salman of any involvement despite widespread allegations that he was behind the killing. Retno said the visit was scheduled after the Saudi monarch visited Indonesia, the world's most populous Muslim-majority nation, in March past year. Police have asked prosecutors and the Saudi consulate for permission to search the vehicle.
Saudi Arabia's king Salman bin Abdul-Aziz al Saud and crown Prince Mohammed Ibn Salman al Saud, in a telephone conversation with the son of the murdered journalist Jamal Saleh Hashtag Hashtag, expressed his deep condolences to all the family and relatives of the deceased.
"The individuals who did this did this outside the scope of their authority", he said.
"That is unacceptable in any government".
On President Donald Trump's consideration for a new tax cut, Tillis said he believed there was a way to "rationalize" the cut in the face of a growing national debt - but warned of "tough choices so we can balance our books". But growing worldwide pressure and comments by U.S. officials up to President Donald Trump forced the kingdom to acknowledge Khashoggi's death.
The foreign ministers of France, Germany and the United Kingdom are demanding that Riyadh provide more facts.
On Sunday, Britain, France and Germany said in a joint statement, "Nothing can justify this killing and we condemn it in the strongest possible terms".
German Chancellor Angela Merkel told reporters in Berlin on Sunday that she supports a freeze on arms exports to Saudi Arabia.