Jamal Khashoggi
Jamal Khashoggi YouTube grab

It is unlikely that Jamal Khashoggi died a "quick and painless" death like his sons hoped. A new audio reportedly suggests that the slain journalist was suffocating moments before he died.

A senior Turkish journalist, who is the head of investigations at the Turkish newspaper Sabah, told Al Jazeera that an audio recording from the Saudi consulate in Istanbul is available, in which the journalist's last words can be heard. "I'm suffocating ... Take this bag off my head, I'm claustrophobic," Khashoggi is heard saying, according to Nazif Karaman.

He also said that the killers took about seven minutes to eliminate the journalist, during which Khashoggi had his head in a plastic bag.

The audio hasn't been made public, but was shared with the United States, Saudi Arabia, Germany, France and Britain, Turkish president Recep Tayyip Erdogan said, adding that Saudi Arabia knows that Khashoggi's killers are among the 15-member squad he spoke about earlier.

It was recently revealed that Khashoggi's body was dismembered after the killing and dissolved in acid to avoid leaving any trace of the murder. Karaman has now said that the killers, before dissolving the body, covered the floor with plastic bags, dismembered the body and then dissolved it in acid, a process that took about 15 minutes.

The process was said to have been carried out at the Istanbul residence of Saudi consul general and traces of acid were also found on the floor. Karaman also said that Sabah would publish the pictures of the tools used in the murder soon, along with a few recordings that detail the last moments of Khashoggi's life.

While Turkish police are now ending the search for Khashoggi's body, sources told Al Jazeera that the criminal investigation into the murder will go on.

The Saudi journalist went missing on October 2 during a visit to the Saudi consulate in Istanbul, Turkey. Since then several speculations have been made and it was also said that Khashoggi himself may have recorded his death, thanks to the Apple Watch he was wearing.

Sabah had earlier said that the scribe had turned on the recording function on his watch before he entered the Saudi consulate, and what went down at the consulate was recorded and sent to his phone and to iCloud.

The newspaper had said that the conversation of the men involved was recorded and so were the moments of his "interrogation, torture and killing." The men then reportedly noticed that the watch was recording and tried to unlock it with several passwords. When they failed, they are said to have used Khashoggi's fingerprint to unlock the watch and delete the recordings.

However, they were reportedly able to delete only a few files, and the rest had already been sent to Khashoggi's phone, which he left with his fiancée waiting outside the consulate. Investigators have now found the recordings on Khashoggi's phone, reported Sabah.

On the contrary, Apple doesn't list fingerprint verification as a feature on the Watch and a company representative also confirmed to CNN that the Apple Watch doesn't come with the fingerprint feature.

It is not known if the investigators found any clues on Khashoggi's phone or icloud.