Fidan, the Istanbul prosecutor, on Wednesday said that Khashoggi was strangled shortly after entering the consulate and that his body was dismembered afterward.
According to a new report by the Armed Conflict Location and Event Data Project (ACLED), a nonprofit conflict-research organization, the Saudi-led war has so far claimed the lives of around 56,000 Yemenis.
"We are looking for answers to the question of where the body is", he said.
Saudi officials have acknowledged that Kashoggi was killed in the consulate on October 2, but say the assailants gave the remains to a third party.More news: Sir Ridley Scott 'moving forward' on Gladiator sequel
Saudi public prosecutor Saud al-Mojeb offered a different explanation last week when he said the killing was premeditated.
The Washington Post also quoted an anonymous Turkish official as saying that their columnist's body was destroyed in acid either on the grounds of the Saudi Consulate or at the nearby residence of the Saudi consul general.
Writing in The Washington Post on Friday, Cengiz said the United States should be leading the worldwide community in seeking justice for Khashoggi.
Hatice Cengiz made her appeal in a video message to a memorial in Washington where friends and activists marked one month since Khashoggi's death and paid tribute to his advocacy for democratic change in the Arab world.
The murder has placed strain on the decades-old alliance between the United States and Saudi Arabia and tarnished the image of Crown Prince Mohammed bin Salman, the kingdom's de facto ruler. She contended that the Trump administration has "taken a position that is devoid of moral foundation" because of fears of "upsetting deals or economic ties".More news: Ariana Grande feels guilty about her anxiety
US Secretary of State Mike Pompeo has indicated that sanctions would soon be imposed on the individuals responsible.
One Israeli official said, "Saudi Arabia is a very important state in the region, and Israel and other nations have a major interest in ensuring its continued stability".
Turkey is seeking the extradition of 18 suspects detained in Saudi Arabia over the journalist's slaying.
A group of US evangelicals, including former Rep. Michele Bachmann (R-MN), held a rare meeting Thursday with Saudi Arabia's crown prince Mohammed bin Salman at his palace.
"The president said we will demand accountability for those who were involved in the commission of this heinous crime", Pompeo said.More news: Fan Asks If Diablo: Immortal Is April Fool's Joke
Earlier on Friday, another Erdogan adviser said the team that killed Khashoggi in Istanbul cut up his body in order to dissolve it for easier disposal, the newspaper Hurriyet reported.