A Turkish court accepted an indictment seeking life sentences for 20 people accused of killing Saudi journalist Jamal Khashoggi, T24 news site reported on Saturday.

The indictment says the accused, which includes the former deputy chief of Saudi Arabia’s intelligence service, Ahmed al-Asiri, and ex-royal adviser Saud al-Qahtani instigated premeditated murder with “monstrous intent”, against Khashoggi.

Khashoggi, a frequent contributor to the Washington Post and a leading critic of the Saudi Crown Prince Muhammad bin Salman, was killed after entering the Saudi consulate in Istanbul in October 2018. The whereabouts of Khashoggi's body remains unknown.

The indictment, prepared by the Istanbul Chief Public Prosecutor’s Office, states that the accused were divided into three units, including intelligence, negotiation and logistics, to carry out the murder, T24 said.

A Saudi court in December sentenced five people to death over the incident, however charges against Asiri and Qahtani were dismissed.

The country's public prosecutor said its investigation found the killing was not premeditated, which contradicts the published findings of a U.N. probe last year. The U.N. found that Khashoggi was the victim of “a deliberate, premeditated execution, an extrajudicial killing for which the state of Saudi Arabia is responsible under international human rights law".

Turkey has demanded Saudi’s cooperation in conducting its own investigation, including assistance in locating Khashoggi’s remains.