The White House on Friday slammed Rep. Joaquin Castro, D-Texas, after he claimed that President Trump's son-in-law, Jared Kushner, may have orchestrated the brutal killing of Saudi writer Jamal Khashoggi -- a claim he walked back later.

The rep told CNN that the Trump adviser and "U.S. intelligence" could have passed around a so-called “enemies list” that was viewed by Saudi Arabia's Crown Prince Mohammed bin Salman. Poppy Harlow, the anchor, challenged Castro, saying the network had no knowledge of the "reporting" he cited. But he responded that he's seen "reporting to that effect."

Sarah Sanders, the White House press secretary, took to Twitter to call out the congressman for presenting the allegations "without a shred of proof." She said it was reprehensible for Castro to cite an article that was "completely debunked."

Castro took to Twitter later in an attempt to clarify his comments. He said he did not intend to accuse Kushner of "orchestrating anything."

"Based on press reporting, I'm asking for Congress to open an investigation of whether any US Intelligence was shared with Saudi Arabia that led to political persecution or killing," he wrote.

Khashoggi was killed in a "fistfight" in the Saudi Consulate in Istanbul, the kingdom claimed early Saturday, finally admitting that the writer had been slain at its diplomatic post. Authorities said 18 Saudi suspects were in custody and intelligence officials had been fired.

The overnight announcements in Saudi state media came more than two weeks after Khashoggi, 59, entered the Saudi Consulate in Istanbul for paperwork required to marry his Turkish fiancee, and never came out. They also contradicted assertions in Turkish media leaks that Khashoggi was tortured, killed and dismembered inside the consulate, claims the kingdom had previously rejected as "baseless."

The Associated Press contributed to this report