On this day four years ago, the world lost a brilliant thought leader, journalist, husband, father and grandfather: Jamal Khashoggi. As his widow, my loss was compounded by the obfuscation of exactly what happened in the days and weeks leading up to his premeditated murder. Key pieces of evidence that hold these answers rest in Jamal’s personal devices: two mobile telephones, a laptop and a tablet. I believe those devices will reveal previously undisclosed details about Jamal’s murder that are critical to knowing the full truth and advancing the cause of justice. Those devices are in the possession of the government of Turkey. Through the critical work of Forbidden Stories, Amnesty International and Citizen Lab, I learned my devices were targeted with the NSO Group’s Pegasus spyware. NSO’s insidious spyware has “zero-click” capabilities which can infect devices, triggering voice and camera surveillance, without the victim ever knowing. Further examination of my devices showed not only tracking by NSO’s spyware, but also evidence that another spyware, Cellebrite, was implanted on my devices and downloaded all my communications with Jamal. All this occurred in 2018, before Jamal’s murder, and while I was under 72 hours of harrowing interrogation by United Arab Emirates intelligence authorities. I was heartbroken to discover that my devices had been compromised, as Jamal and I constantly discussed our plans for the future, including our travel plans. Who was listening in on us and when? Is this how they knew Jamal’s every movement and travel plans? I suspect Jamal’s phones were equally compromised by NSO’s Pegasus spyware at the direction of the Saudi government. In 2019, Dr Agnès Callamard, the former UN special rapporteur who investigated my husband’s murder, asked for his devices and was told by Turkish authorities that they were holding Jamal’s phones and his computer as part of their investigation, and the examination of those devices were “ongoing”. I hoped that during the highly anticipated trial in Turkey, the prosecutor would reveal key evidence they had collected on Jamal’s devices. But this was never to be, as the trial in Turkey has been halted and moved to Saudi Arabia without any answers. My attorney, Randa Fahmy, made a recent request for these devices through Hasan Murat Mercan, the Turkish ambassador to the US. I have personally asked the Turkish president, Recep Tayyip Erdoğan, for my husband’s devices – to no avail. Last week, I turned to the US director of national intelligence, Avril Haines, to assist me in securing them. I asked her to formally request that Turkey return these key pieces of evidence, in light of impending legal action in the US. The Turkish government has been clear that it does not intend to proceed with either the investigation into my husband’s murder or the trial. It should therefore hand over any evidence still in its hands to me. As the only wife of Jamal upon his death, I want all parties to be held accountable for my husband’s murder, including the governments of Saudi Arabia, the UAE and the NSO Group. It is critical to the cause of justice to know if Jamal’s devices were infected by NSO’s spyware. Turkey should surrender those devices now. Hanan El Khashoggi is the widow of Jamal Khashoggi, a Saudi journalist and Washington Post columnist who was killed on 2 October 2018 at the Saudi consulate in Istanbul, Turkey