A Turkish prosecutor has demanded that arrest warrants be issued against two Saudi nationals close to Crown Prince Mohammed bin Salman over the murder of journalist Jamal Khashoggi.

The Istanbul Chief Prosecutor’s Office filed an application December 5 to obtain the warrants for Ahmad al-Assiri and Saud al-Qahtani, described in court documents as being “among the planners” of the murder of the Washington Post contributor.

The court application said there is “strong suspicion” the two aides were involved in planning the killing, Hurriyet Daily News reports.

Turkey has been seeking to extradite 18 suspects, including 15 members of the alleged assassination squad.

Saudi Arabia had detained 21 people and says it is seeking the death penalty for five. Assiri and Qahtani were reportedly suspended from their duties but they do not face criminal charges.

“The prosecution’s move to issue arrest warrants for Asiri and Qahtani reflects the view that the Saudi authorities won’t take formal action against those individuals,” Reuters quoted one Turkish official as saying on Dec. 5.