Speaking at a campaign event at Allen University on Thursday, New Jersey Democratic Sen. Cory Booker criticized the White House’s handling of Khashoggi's disappearance, saying Washington should reevaluate its close ties with Riyadh.

"We need to reexamine that entire relationship,” said Booker. "We need to be a nation that leads the moral light of the world, not retreats from our morals."

The senator said Khashoggi "died gruesomely, which is horrific, and we should condemn it".

Khashoggi has been missing since Oct. 2 when he entered the Saudi consulate in Istanbul.

On the same day of Khashoggi's disappearance, 15 other Saudis, including several officials, arrived in Istanbul on two planes and visited the consulate while he was still inside, according to Turkish police sources. All of the identified individuals have since left Turkey.

On Wednesday, crime scene investigation units arrived at the official residence of Saudi Consul General Mohammad al-Otaibi around 4.40 p.m. local time (1340GMT). Al-Otaibi had left Turkey for Riyadh on Tuesday.

Officials from a joint Turkish-Saudi team completed an investigation into the case early Thursday after searching the residence as well as the Saudi consulate in Istanbul.

Earlier in the day, U.S. President Donald Trump said it "certainly looks" like Khashoggi is dead, amid speculation he was killed by Saudi agents.

"We're waiting for some investigations, and waiting for the results, and we'll have them very soon. And I think we'll be making a statement, a very strong statement, but we're waiting for the results of about three different investigations," he told reporters before departing for a campaign rally in Montana.

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