A symbolic funeral for murdered Saudi journalist Jamal Khashoggi was held in Istanbul on Friday, as revelations from the investigation into his death continued to emerge.

Prayers were also said in Mecca and Medina and mourners paid their respects to his family in Jeddah.

Khashoggi, a Washington Post contributor and critic of the Saudi leadership, was last seen entering the kingdom's Istanbul consulate on October 2. Riyadh has admitted he was killed there and his body disposed of, but has given shifting accounts about his death.

In the absence of a body, dozens of people gathered at Fatih mosque in Istanbul on Friday in front of an empty platform traditionally reserved for the coffin. Mourners listened to Koranic recitations and friends eulogised the 59-year-old journalist.

"We decided to hold the prayers as we are convinced that his body will never be found," Fatih Oke, executive director of the Turkish-Arab Media Association (TAM) of which Khashoggi was a member, told AFP news agency. 

The ceremony which took place under rain, "is a message delivered to the world to say that the murder will not go unpunished and that justice will be served," said Ibrahim Pekdemir, an Istanbul resident who attended.

In the Saudi coastal city of Jeddah, two of Khashoggi's brothers and one of his sons received a few hundred men who paid their respects.

The reception included veteran Saudi journalists and former senior officials who had worked with Khashoggi, as well as senior US and British diplomats.

Tens of thousands of worshipers meanwhile prayed for the deceased in Mecca and Medina, Khashoggi's hometown, though the imams did not name him.

Khashoggi's son Salah told CNN last week that he wanted to bury his father in Medina with the rest of the family, saying "We just need to make sure that he rests in peace."

Khashoggi's Turkish fiancee, who had waited outside the consulate on the day he was killed, tweeted a selfie of him on Thursday, writing: "Dear Jamal.. rest in peace. We will meet in heaven inshallah (God willing)..!"

A second audio tape?

Turkey has insisted Khashoggi's death was a premeditated killing.

Saudi authorities however say the operation that led to his death -- involving a 15-man team sent by Riyadh to Istanbul -- was meant to repatriate him alive.

On Friday, the Turkish daily Hurriyet reported that Turkey had more evidence, including a new audio tape, contradicting the Saudi version of events.

The tape, of the moment shortly before the journalist arrived, clearly showed the murder was planned in advance, according to Hurriyet columnist Abdulkadir Selvi.

A first tape obtained by Turkish investigators allegedly proved that Khashoggi was strangled.

Turkish President Recep Tayyip Erdogan has said the order to murder Khashoggi came from "the highest levels" of the Riyadh government, but has stopped short of pointing the finger at Crown Prince Mohammed bin Salman. 

Allegations of a cover-up by Saudi Arabia have also put a strain on relations with the US, a traditional ally.

On Friday, sources familiar with the matter said the CIA believes Prince Mohammed ordered Khashoggi's killing. Both the White House and the State Department declined to comment.

Saudi prosecutors have indicted 11 people and 21 individuals are in custody in connection with the killing. Prosecutors have also said they are seeking the death penalty for five unnamed accused, "charged with ordering and committing the crime."

(Top picture: Salah Khashoggi (R), the son of murdered Saudi journalist Jamal Khashoggi, receives mourners in Jeddah, Saudi Arabia, November 16, 2018. /VCG Photo)