The United States is urging Saudi Arabia to locate the body of slain journalist Jamal Khashoggi and return it to his family as soon as possible.

Khashoggi was killed when he walked into the Saudi consulate in Istanbul last month, according to a Turkish prosecutor. His body has not been found, although Turkish police last month searched a forest on Istanbul’s outskirts and near Yalova, a city near the Sea of Marmara, for Khashoggi’s remains.

Khashoggi’s friends and family say they want just a piece of his body so they can carry out his wish to be buried in the city of Medina, Islam’s second holiest site.

“We are calling the entire world to put the necessary pressure, international pressure, on the Saudi government to find his remains, to be able to bury him, even before finding those who are responsible, before this issue is covered up,” Faith Oke, executive director of the Turkey-Arab Media Association, said Thursday.

Turkish officials said chief prosecutor Irfan Fidan failed to get answers about the location of Khashoggi’s body and who ordered his killing during three days of a joint Turkish-Saudi investigation in Istanbul.

The Saudis have given a shifting account of what happened to Khashoggi on Oct. 2. After initially denying Khashoggi had been killed, the Saudi government claimed he died in an unplanned “rogue operation.” Saudi public prosecutor Saud al-Mojeb offered a different explanation last week when he said the killing was premeditated.

After talks with Mojeb earlier this week, Fidan also said the killing was premeditated, with Khashoggi being suffocated immediately after entering the consulate and his body dismembered.

Turkey is trying to extradite 18 suspects detained in Saudi Arabia so they can be tried in a Turkish court. Among the suspects are 15 members of an alleged “hit squad” that Turkey claims was sent to Istanbul to kill The Washington Post columnist who had written critically of Saudi Crown Prince Mohammed bin Salman.

Some of the people suspected of being involved in the killing have close ties to the prince, whose condemnation has failed to alleviate suspicions he was involved.

Khashoggi entered the consulate last month to get a document he needed to marry his Turkish fiancee.