When Charlie Sennott, the CEO of the Groundtruth Project and an analyst for WGBH News, covered Saudi Arabia for The Boston Globe, there was one person he knew he could rely on to help him understand the nation: Jamal Khashoggi.

“[He was] one of the most important voices in Saudi Arabia, a guy I used to go see regularly,” Sennott said during an interview with Boston Public Radio on Monday. “When you went to try and understand Saudi Arabia, he was the first person you went to.”

In October 2018, Khashoggi, who was an American resident and journalist for The Washington Post, was seen entering the Saudi consulate in Istanbul, and according to security footage, never left. Several nations, including Turkey, the United Kingdom, France and Germany immediately cast blame on the Saudis, who claimed later in the month that Khashoggi had died during a fight inside the consulate. Audio evidence provided by Turkey to various governments, and confirmed by Canadian Prime Minister Justin Trudeau among others, revealed that Khashoggi was tortured inside the consulate, and after his body was dissected with a bonesaw and carried out of the consulate.

“They didn’t just kill him,” Sennott said. “They murdered him in the most brutal fashion.”

Speculation abounded that Khashoggi’s murder was ordered by Saudi Crown Prince Mohammed bin Salman, who has denied all the accusations. During an interview with “60 Minutes” on Sunday, Salman spoke to a member of the press for the first time since the killing and called Khashoggi’s murder a “mistake,” but denied he had any involvement.

Sennott said Khashoggi’s death was a dark mark on the legacy of the United States, and challenged President Donald Trump to take a harsher tone when dealing with Saudi Arabia in retaliation.

“The Saudis are very much looking to the United States for support as an ally in the region,” Sennott said. “I think at a time when they need us, they need to hear loud and clear that these kinds of human rights violations won’t stand.”