A member of the team allegedly sent to kill Saudi journalist Jamal Khashoggi, was recorded saying on a phone to "tell your boss" that the mission had been carried out, the New York Times reports.
The call occurred shortly after Khashoggi was killed last month at the Saudi Consulate in Istanbul.
The 'boss' is believed to be a reference to Crown Prince Mohammed bin Salman, according to New York Times sources "familiar with a recording of Khashoggi's killing collected by Turkish intelligence".
The newspaper says the recording is "seen by intelligence officials as some of the strongest evidence linking Prince Mohammed to the killing of Mr Khashoggi".
Maher Abdulaziz Mutreb, a security officer, made the call. He said words to the effect of "the deed was done".
"A phone call like that is about as close to a smoking gun as you are going to get," Bruce Riedel, a former CIA officer, told the New York Times. Riedel, now at the Brookings Institution, added: "It is pretty incriminating evidence."
Meanwhile, a Turkish newspaper reports that the last words of Khashoggi reveal the way he pleaded with his murderers moments before his death, the Daily Mail reports.
The Daily Sabah says they will soon publish images of the tools used by a team of 15 people who are suspected of slaying the Washington Post writer, and claim to have heard his final utterances in secret audio recordings on October 2.
"I'm suffocating … Take this bag off my head, I'm claustrophobic," Khashoggi said according to the head of investigations for the Turkish newspaper, Nazif Karaman.
Karaman told Al Jazeera in an interview that the hit squad placed plastic bags down to protect the floor before dismembering Khashoggi.
The Turkish newspaper claims it took 15 minutes to carry out the grisly killing and traces of acid were discovered at the Saudi consul general's home in Istanbul.
It's believed the body was taken there to be disposed of using chemicals.