After Saudi Arabia acknowledged last year that its agents had killed and dismembered Jamal Khashoggi, the kingdom vowed to prosecute the culprits. The Saudi authorities, as promised, have indeed put on a trial.

But it is clouded in secrecy, the court sessions closed to the public and journalists. Every detail of the trial proceedings — their frequency, the names of the 11 defendants and the exact charges they face — is a matter of speculation.

U.S. and Western intelligence officials have stood by their assessment that Saudi Crown Prince Mohammed bin Salman ordered the operation that ended in Khashoggi’s death. But no single piece of evidence definitively linking the prince to the crime has emerged in the past six months, officials said.

In the meantime, some details of the trial have emerged. Diplomats from the United States and several European countries have been allowed to attend, as has a member of Khashoggi’s family, Reuters reported. In several of the court sessions, defendants had pleaded “not guilty,” a U.S. official said.

The defendants are said to include two of the most prominent members of the “kill squad” allegedly sent to confront Khashoggi in the Istanbul consulate: Maher Mutreb, the leader of the squad, and Salah al-Tubaigy, an autopsy specialist who is believed to have dismembered Khashoggi’s body. At least one high-ranking Saudi official, Ahmed ­al-Assiri, is also a defendant, according to Reuters.

But Saud al-Qahtani, a close aide to the crown prince, is not on trial, according to people briefed on the case, though the U.S. government has imposed sanctions on him because of his suspected role in the plot. His absence has led to accusations that Saudi Arabia is throwing mostly lower-level soldiers to the wolves rather than aggressively pursuing justice in the case.

“The government of Saudi Arabia is grievously mistaken if it believes that these proceedings, as currently constituted, will satisfy the international community,” Agnès Callamard, a U.N. human rights expert who is investigating the killing, said last month in a statement that demanded more transparency from Saudi authorities as they conducted the trial.