The report by FTI Consulting concluded that massive amounts of data began leaving Bezos' phone about a month after the video was shared in mid-2018, the person told Reuters, declining to be identified due to the sensitivity of the subject.
The UN experts reviewed a 2019 digital forensic analysis of Bezos's iPhone, which they said was made available to them as UN special rapporteurs.
The report said digital forensic analysis of the Amazon boss's phone first began early a year ago following the publication of revelations about Mr Bezos's private life in U.S. tabloid the National Enquirer, which included private text messages.
"The circumstances and timing of the hacking and surveillance of Bezos also strengthen support for further investigation by USA and other relevant authorities of the allegations that the Crown Prince ordered, incited, or, at a minimum, was aware of planning for but failed to stop the mission that fatally targeted Mr. Khashoggi in Istanbul", Callamard and Kaye said.
Back in 2018, Jeff Bezos and the Saudi crown prince were seen laughing together on the sidelines of an event.
Saudi Arabia has repeatedly denied accusations that the crown prince engineered the death of Khashoggi, blaming rogue agents instead and the kingdom's public prosecutor has since charged 11 people over his murder.
De Becker and Amazon didn't immediately respond to messages seeking comment.
Bezos founded the online retail platform Amazon, and also owns The Washington Post, the outlet Jamal Khashoggi wrote for before his murder.
However, at the time of writing, it's unclear whether the alleged hack of Bezos's phone also leaked any sensitive corporate information related to Amazon.
On Tuesday, The Financial Times reported on the stunning allegation, which comes from a forensic analysis Bezos commissioned to determine the culprit behind the hack.
The allegations could nonetheless further damage relations between tech tycoon Mr. Bezos and Riyadh, and risk harming the kingdom's reputation with foreign powers and investors.
United Nations experts Agnes Callamard and Davie Kaye, who were given a copy of the forensics report, said the breach of Bezos' phone was part of "a pattern of targeted surveillance of perceived opponents and those of broader strategic importance to the Saudi authorities". But Bezos's investigation concluded with "high confidence" that Saudi Arabia had hacked Bezos' phone and collected "private information" about him.