Turkey is waiting for Saudi Crown Prince Mohammed bin Salman to shed light on the killing of journalist Jamal Khashoggi at the Saudi Consulate in Istanbul last month, the country’s president was quoted as saying Tuesday.

Speaking to journalists on board his plane while returning from World War I commemorations in Paris, Recep Tayyip Erdogan also reportedly said audio recordings of the killing that Turkey shared with officials from Saudi Arabia and other nations were so “atrocious” that a Saudi intelligence official speculated that the killer may have been on heroin.

“The recording is truly atrocious. In fact, when the Saudi intelligence officer listened to the recording he was so shocked that he said ‘this one probably took heroin. Only someone who took heroin would do it,'” Erdogan was reported as saying in comments published in pro-government Yeni Safak.

Turkey says The Washington Post columnist, who had criticized the crown prince, was killed by a 15-member assassination squad sent from Riyadh. Ankara insists the orders for the killing came from the highest levels of the Saudi government, but not King Salman.

The crown prince has come under scrutiny for having knowledge of the killing, which involved some members of his security entourage.

Pressing ahead with moves to maintain pressure on Saudi Arabia, Erdogan said the crown prince had told Turkish envoys that he would shed light on the Oct. 2 killing at the kingdom’s consulate and do what was “necessary.”

“He said this to my special envoys,” Erdogan was quoted as saying. “We are waiting patiently.”

Erdogan repeated that Turkey had shared audio recordings relating to the killing with Saudi Arabia and other nations, including the United States, Britain, France, Germany and Canada.

Under mounting pressure, Saudi Arabia has changed its narrative about Khashoggi’s killing. It first said he walked out of the embassy the day he disappeared before eventually acknowledging Khashoggi died inside the consulate. Saudi Arabia has also recently acknowledged Turkish evidence that showed the slaying was premeditated.

Turkey says a 15-member Saudi “hit squad” strangled and dismembered Khashoggi at the consulate. Media reports have suggested that his body could have been chemically dissolved as it has not yet been found.

Saudi officials characterize the killing as a rogue operation carried out by Saudi agents who exceeded their authority.