Turkish President Recep Tayyip Erdogan says the order for Saudi journalist Jamal Khashoggi's killing came from the highest level of the Saudi government.
In an op-ed in The Washington Post on Friday, Erdogan says, "we must reveal the identities of the puppet masters behind Khashoggi's killing".
The Turkish president said he did not believe that Saudi King Salman had ordered the killing.
He said Turkey's friendship with Riyadh did not mean that Turkey could turn a blind eye to the killing of the journalist last month in the Saudi consulate in Istanbul.
Khashoggi, a columnist for The Washington Post, was killed inside the Saudi consulate in Istanbul on October 2.
Earlier his fiancee Hatice Cengiz called for US President Donald Trump's help in pressuring Saudi Arabia to reveal the location of his body.
Cengiz made her appeal in a video message to a memorial in Washington on Friday where friends and activists marked one month since Khashoggi's death.
"I would like him to support Turkey's efforts in trying to bring light to this situation and to discover the whereabouts of his body," Cengiz said.
Istanbul's chief prosecutor announced on Wednesday that Khashoggi was strangled immediately after he entered and that his body was dismembered and removed from the consulate.
Turkish presidential adviser Yasin Aktay was quoted by Turkish newspaper Hurriyet on Friday saying that after being dismembered, Khashoggi's body was dissolved using a chemical substance.
Turkey is seeking the extradition of 18 suspects so they can be put on trial in Turkey.
They include 15 members of an alleged Saudi "hit squad" that Turkey says was sent to Istanbul to kill Khashoggi, who lived in exile in the United States and had written critically of Saudi Arabia's Crown Prince Mohammed bin Salman.
Some of those implicated in the killing are close to the prince, whose condemnation of the murder has failed to ease suspicions that he was involved.
Saudi Arabia has changed its narrative about Khashoggi's killing several times, but has recently acknowledged that Turkish evidence shows it was premeditated.
Trump has condemned Khashoggi's killing in strong terms but has also defended US arms sales to Saudi Arabia, which is the biggest foreign customer for American weaponry.
