The UN report into the murder of Jamal Khashoggi reveals disturbing new details about what happened in the hours before he died, and the conversations that were taking place between Saudi officials who were involved in his killing.

Relying on the transcripts of recordings provided by the Turkish authorities, the report describes how Jamal Khashoggi went to the Saudi consulate in Turkey by appointment on 2 October last year, to obtain papers he needed to pave the way for his marriage to his fiancée, Hatice Cengiz.

Saudi Arabia had been trying to get him to return from the US, where he worked as a journalist for the Washington Post, but he feared for his safety.

The report relies on recordings of conversations within the consulate in the days prior to his death, which show how a team of Saudi officials flew from Riyadh to Istanbul to kill him. Five came on a commercial flight, nine others on a private jet.

In a recording from inside the consulate on 1 October, one man was recorded saying: “A commission is coming from Saudi Arabia tomorrow. They have something to do in the consulate … Their work inside will take two or three days.”

There were discussions that day about a farmhouse in Yalova, a city on the coast of the Sea of Marmara, and its isolated position. When an official is told “there is nobody there … just a caretaker”, he replies, “Very nice.”

The report then outlines conversations that took place shortly before Khashoggi arrived at the Turkish consulate on the day he died.

One Saudi official asked whether it would “be possible to put the trunk in a bag”. Another replied: “No. Too heavy. It is not a problem. The body is heavy. First time I cut on the ground. If we take plastic bags and cut it into pieces, it will be finished. We will wrap each of them.”

Khashoggi entered the consulate at 1.15pm, the report says. He was invited to the office of the consul general located on the second floor.

According to recordings, the conversation with him first focused on whether he would go back to Saudi Arabia. An official told him: “We will have to take you back. There is an order from Interpol. Interpol requested you to be sent back. We are coming to get you.”

He was asked about his two phones and told to type a message, which he refused to do, the special rapporteur says.

According to the recordings, Khashoggi said: “What should I say? See you soon? I can’t say kidnapping. I will not write anything.”

An official then said to him: “Type it, Mr Jamal. Hurry up. Help us so that we can help you because at the end we will take you back to Saudi Arabia and if you don’t help us you know what will happen at the end; let this issue find a good end.”

At 1.33pm, Khashoggi could be heard saying: “There is a towel here. Are you going to give me drugs?”

“We will anaesthetise you,” came a reply.

In the recordings, sounds of a struggle can be heard, the UN report says, and then voices saying: “Did he sleep? … Keep pushing … Push here. Don’t remove your hand. Push it.”

The report adds: “The sound of plastic sheets (wrapping) could also be heard. Turkish intelligence concluded that these came after Mr Khashoggi’s death while the Saudi officials were dismembering his body.”